BEL Trainee Engineer Electronics Mock Test - 6 Free MCQ Practice Test with Solutions - Electronics and Communication Engineering (ECE) (2024)

Hexadecimal representation system

A is represented by 1010 and 4 is represented by 0100.

4A = 01001010

The left most number is 0, so 4A can be represented as1001010

Pentavalent impurities:

Impurity atoms with 5 valence electrons produce n-type semiconductors by contributing an extra electron.

This is as explained in the figure:

The energy band diagram for an n-type semiconductor will be as shown:

Trivalent Impurities:

Impurity atoms with 3 valence electrons produce p-type semiconductors by producing a "hole" or an electron deficiency.

The correct answer is option 3.

Concept:

The given circuit is,

The resultant expression is,

Y= (A+B). C.D.E here(.) is and operation and (+) is or operation

Y=(A+B).CDE

This is also written as,

Y=C(A+B)DE

Hence the correct answer isC(A+B)DE.

The total noise output is defined in terms of the effective noise temperature (T_e) as:

If the Amplifier is assumed to have a power gain of G, then the Noise output power P_no will have two components:

P_na, the power of the amplifier output due to internal noise generated.

The input source noise that is amplified by the network.

= Effective noise temperature

Calculation:

Given T = 30 K

G(dB) = 100 dB

So, G = 10¹⁰

T_e= 270 K ; B = 1.5 MHz

K = 1.38 × 10^-23 eJ/K

∴

The correct answer is option 3.

Concept:

Statement 1:TheUniform Resource Identifieris a set of rules which is used to retrieve linked web pages across the web.

False,The HyperText Transfer Protocol is a set of rules which is used to retrieve linked web pages across the web. The more secure and advanced version is HTTPS.

HTTP is a protocol for fetching resources such as HTML documents. It is the foundation of any data exchange on the Web and it is a client-server protocol, which means requests are initiated by the recipient, usually the Web browser.

Statement 2:HyperText Transfer Protocolis a unique address or path for each resource located on the web.

False,URI (Uniform Resource Identifier) or URL (Uniform Resource Locator) is a unique address or path for each resource located on the web.

A Uniform Resource Identifier (URI) is a character sequence that identifies a logical (abstract) or physical resourceusually, but not always, connected to the internet.

Hence the correct answer isBoth statement 1 and statement 2.

Concept:

Admittance (Y) is the measurement quantity that tells us how easily a conducting device can allow the flow of current through it.

Admittance can be defined as a reciprocal of impedance (Z). i.e

Y = 1/Z

Admittance measures the flow of current allowed by the circuit which is the inverse of the impedance function.

Calculation:

Given;

An RC circuit having

R = 15Ω

C = 0.1 mF

f = 50 Hz

ω = 2πf = 100π = 314 rad/sec

Then

Z = R + 1/jωC = 15 + j31.83 = 35.18∠64.76°

Y = 1/Z = 0.03∠-64.76°

Hence, option 1is the correct Answer.

Advantage of AM:

• The advantages of AM radio are that it is relatively easy to detect with simple equipment, even if the signal is not very strong.
• It has a narrower bandwidth than FM, and wider coverage compared with FM radio.
• Its use avoids receiver complexity.

Disadvantages of AM:

• In AM most of the transmitted power is in a carrier that contains no information.
• It is affected by noise.
• In AM if there are two more signals received at the same frequency, then both will be demodulated which can lead to interference.

Important differences between AM and FM are elaborated in the table below:

Important Point

Photodiode:

• A photodiode can convert light into either current or voltage depending upon the mode of operation.
• It is designed to operate in reverse bias.

Advantages of Photodiode:

• The photodiode is linear
• Low resistance
• A very good spectral response
• Better frequency response
• Low dark current
• Fastest photodetector
• It can be used as a variable resistance device
• Long lifetime, Low noise, High quantum efficiency, It is highly sensitive to the light
• Compact and lightweight
• No high voltage requires
• Using photodiode the speed of operation is very high

Disadvantages of Photodiode:

• Require increases inthe dark current
• It depends on the temperature
• Small active area
• Normal PN junction photodiode has a very high response time
• It has very low sensitivity
• Light sensitive device
• Poor temperature stability

Sampled data system:

When the signal or information at any or some points in a system is in the form of discrete pulses, then the system is called discrete data system or sampled data system.

The following methods suitable for the stability analysis of sampled data control systems.

• Jury’s stability test
• Root locus technique
• Bilinear transformation

Merits:

• Systems are highly accurate, fast and flexible
• Use of time sharing concept of digital computer results in economical cost and space.
• Digital transducers used in the system have better resolution.
• The digital components are less affected by noise, non-linearities and transmission errors of noisy channel.

Demerits:

• Conversion of analog signals to discrete-time signals and reconstruction introduce noise and errors in the signal.
• Additional filters have to be introduced in the system if the components of the system does not have adequate filtering characteristics.

Since at t = 0, the switchis closed.

So at t > 0, the circuitwill be.

Redrawing above circuit in s-domain –

i(t) = 10 u(t) Amp

NOTE:

Since the switch is closed t ≥ 0

So 10 V will work only after t ≥ 0 that’s why we take voltage source as 10 u(t). In Laplace or s-domain

The correct answer is (option4) i.e. 0 A

Concept:

• We have taken the example of A.C. the bridge here.
• Here we can clearly see that there are a total of 4 arms and one detector connected.
• For a balanced bridge, the detector shows zero deflections.

The condition for the balanced bridge is

So if the ac bridge is balanced, then the current through the detector is 0 A.

Additional Information

Concept:

The time constant for an RC circuit is given by:

τ = R_eqC

While calculating the time constant, independent must be replaced by their internal impedances.

Calculation:

R_eq= 1+ 2Ω

R_eq= 3Ω

τ = 3× 1

τ = 3 sec

Additional Information
The time constant for an RL circuit is given by:

Concept:

The probability of bit error is proportional to the distance between the closest points in the constellation diagram.

The bit error decreases as the distance increases.

Application:

Since the Probability of error is the same in both cases, the minimum distance must equal for the given pair of signal points.

For the first constellation, the minimum distance between two adjacent signal points is 2A.

For the second constellation, the minimum distance is:

Equating the two distances, we get:

4 A² = A₁² + A₂²

Also, the average Power in QPSK will be:

Average Power in QAM

⇒ 2A²

Hence Average power is the same in both diagrams.

A practical voltmeter must have a very high input resistance value (Ideally Infinite).

A voltmeter measures the voltage difference between the two different pointsbut it should not change the amount of current going through the element between these two points.

So it should havehigh resistance so thatit doesn't draw current through it.

Values of input resistance

Concept:

Pulse code modulation is a technique to change an analog signal to digital data. A large bandwidth is required in PCM system.

Explanation:

A PCM encode contain three components:

1) The analog signal is sampled

2) The sampled signal is quantized

3) The quantized values are encoded as stream of bits

Diagram:

Cleavage plane:

• When a crystal is break or fracture easily along a definite plane then this plane is called cleavage plane.
• It is used to identity mineral and its quality.
• It forms generally in a lower energy crystal structure.
• In silicon, most preferred cleavage plane is < 111 >

Silicon have two cleavage plane < 111 > and < 110 >

The correct answer is option 4.

Concept:

Options verify the best way to solve the problem.

Option 1:8, 11

703x(in base-x number system) = 504y(in base-y number system)

703_x=504_y

(703)₈=(504)₁₁

451=609

LHS is not equal to RHS.

Option 2:12, 13

703x(in base-x number system) = 504y(in base-y number system)

703x=504y

(703)₁₂=(504)13

1011=849

LHS is not equal to RHS.

Option 3:17, 18

703x(in base-x number system) = 504y(in base-y number system)

703x=504y

(703)17=(504)18

2026 =1624

LHS is not equal to RHS.

Hence the correct answer isNone of these.

Explanation:

Sensitivity: The parameters of a control system are always changing with the change in surrounding conditions, internal disturbance, or any other parameters.

This change can be expressed in terms of sensitivity. Any control system should be insensitive to such parameters but sensitive to input signals only.

Now there are two types of control systems:

1. Open-loop control system

2. Closed-loop control system

Open-loop control system:

1. A control system in which the control action is totally independent of the output of the system. A manual control system is also an open-loop control system.

2.The sensitivity function for the overall open loop system is one.

Closed-loop system:

1. Control systems in which the output has an effect on the input quantity in such a manner that the input quantity will adjust itself based on the output generated

2. The sensitivity function for the closed-loop function is:

Hence the sensitivity of the closed-loop system is reduced by a factor (1 + G(s)H(s)) as compared to the open-loop system.

An automatic Washing Machineis an example of an open-loop system asthemachine runs according to the pre-set time irrespective of washing is completed or not.

Automatic intensity adjustable light bulb is an example of a closed-loop system that controls the light intensity automatically as required dependingon the daylight conditions with the help of feedback sensors connected to it.

Hencean automatic Washing Machineis moresensitive to the variation in system's gain as compared to an automatic intensity adjustable light bulb.

Hence option (4) is the correct answer.

• A point-to-point connection provides a dedicated link between two devices
• In mesh, star and ring topologies are a point-to-point connection
• In a star topology, each device needs only one link and one I/O port to connect it to any number of other devices
• In a ring topology, each device has a dedicated point-to-point connection with only the two devices on either side of it; Each device is connected to its corresponding repeater
• In a mesh topology, every device has a dedicated point-to-point link to every other device
• Amultipointconnection is one in which more than two specific devices share a single link
• In Bus Topology, one long cable acts as a backbone to link all the devices in a network

Potential field ϕ = 2xy² – 3y²z

Now, electric field intensity at (0, 1, 0) is,

E = -∇ϕ

At the given point (0, 1, 0)

⇒ x = 0, y = 1, z = 0

E = (-2x̂ + 3ẑ) V/m

Concept:

The numerical aperture of fiber optic cable is given by

Where n1and n2arecore and cladding refractive indices

Intersymbol Interference (ISI):

• It is a form of distortion, where one symbol interferes with subsequent symbols.
• ISI causes due to the spreading of pulse width beyond its limit.
• Due to ISI decision device shows error at the receiver.
• A major cause to arise ISI is multipath propagation and transmission of the signal through a band-limited channel.
• ISI can be analyzed with the help of an eye diagram:

• Eye diagram can be observed in an oscilloscope
• The width of the eye diagram represents wave can be sampled without ISI in an interval.
• The height of the eye-diagram represents wave is sampled at a specific time that defines the margin over the noise.

The correct answer is Broadcast.

Key Points

• IP stands for Internet Protocol is a unique address that identifies a system or any device that works on the internet.
• It sets certain rules for transferring data over the internet.
• There are various types of IP addresses like Public IP address, Private IP addresses, Dynamic and Static IP addresses etc.
• Based on the number of bits, there are two versions of IP address: IPv4 and IPv6.
• IPv6 is a 128-bit hexadecimal address separated into 8 groups of 16 bits by a colon.
• Here, the first 48 bits are network IDs, the next 16 bits are subnet IDs, and the last 64 are client IDs.
  

• There are three types of IPv6 transmission. They are Unicast, Anycast and Multicast. Hence option 2 is correct.
• A Unicast type uniquely identifies a singleinterface on an IPv6 device. A packet sent to a unicast address destination travels from the sourcehost to the destination host.
• Anycast address identifiesthe set of interfaces at different locations in such a way that a packet sent to an anycast address will be delivered to a member of the set.
• Multicast addresses identify a group of interfaces such that a packet sent to a multicast address is delivered to all the interfaces in the group.

Additional Information

• IPv4 is a 32-bit address, first deployed by ARPANET (Advanced Research Projects Agency Networks).
• IPv4 transmission types are Unicast, Multicast and Broadcast.
• Broadcast in IPv4 is a network address that is used to transmit to all the devices connected to multiple networks. The message sent to a broadcast is received by all hosts.

Finite Impulse Response (FIR) filter

• In signal processing, a finite impulse response (FIR) filter is a filter whose impulse responseis of finite duration because it settles to zero in finite time.
• FIR filters can be discrete-time or continuous-time, and digital or analog.
• The impulse responseof an Nth-orderdiscrete-timeFIR filter hasexactly N+1 samples.
• For a linear-phase filter, group delay and phase delay are of the same value. So linear-phase filters are also called Constant Time Delay Filters.
• An FIR filter is a linear phase if its coefficients are symmetrical or anti-symmetrical around the center coefficient.

Concept:

For the MOD-Nasynchronous counter, the number of T flip-flops is given by:

MOD-N≼ 2^N

where N = No. of flip-flops

Calculation:

MOD 10≼ 2N

N = 4

Therefore, the number of T flip-flops required to realize a mod-10 asynchronous counter is 4.

Wien-Bridge Oscillator:

• One of the simplest sine wave oscillators which use an RC network in place of the conventional LC tuned tank circuit to produce a sinusoidal output waveform is called a Wien Bridge Oscillator.
• A Wien-Bridge Oscillator is a type of phase-shift oscillator which is based upon a Wien-Bridge network shown below in figure (a)comprising four arms connected in a bridge fashion.
• Here two arms are purely resistive while the other two arms are a combination of resistors and capacitors.

• In particular, one arm has a resistor and capacitor connected in series (R₁ and C₁) while the other has them in parallel (R₂ and C₂).
• This indicates that these two arms of the network behave identically to that of a high pass filter or low pass filter,the behavior of the circuit shown in Figure (b).
• In this circuit, at high frequencies, the reactance of the capacitors C₁ and C₂ will be much less due to which the voltage V₀ will become zero as R₂ will be shorted.
• Next, at low frequencies, the reactance of the capacitors C₁ and C₂ will become very high.
• However, even in this case, the output voltage V₀ will remain at zero only, as the capacitor C₁ would be acting as an open circuit.
• This kind of behavior exhibited by the Wien-Bridge network makes it a lead-lag circuit in the case of low and high frequencies, respectively.

Wien bridge oscillator frequency calculation:

• In between these two high and low frequencies, there exists a particular frequency at which the values of the resistance and the capacitive reactance will become equal to each other, producing the maximum output voltage.
• This frequency is referred to as the resonant frequency (f_r).
• The resonant frequency for a Wein Bridge Oscillator is calculated using the following formula given below

If R₁ = R₂ = R and C₁ = C₂ = C

then

• The Wien Bridge oscillator is a two-stage RC coupled amplifier circuit that has good stability at its resonant frequencyand low distortion.
• It is very easy to tune making it a popular circuit as an audio frequency oscillator but the phase shift of the output signal is considerably different from the previous phase shift RC Oscillator.
• ​The Wien Bridge Oscillator uses a feedback circuit consisting of a series RC circuit connected with a parallel RC of the same component values producing a phase delay or phase advance circuit depending upon the frequency.
• At the resonant frequency (ƒr) the phase shift is 0oin the Wien Bridge oscillator.

Additional Information
Schering bridge:

• This bridge is used to measure to the capacitance of the capacitor, dissipation factor and measurement of relative permittivity.
• The circuit diagram of the Schering bridge is shown below:

Hay’s bridge:

• The bridge gives a very simple expression for the calculation of unknown inductors of high value.
• The circuit diagram of Hay's bridge is shown below:

Maxwell’s bridge:

• The bridge used for the measurement of self-inductance of the circuit is known as the Maxwell bridge. It is the advanced form of the Wheatstone bridge.
• The Maxwell bridge works on the principle of comparison, i.e., the value of unknown inductance is determined by comparing it with the known value or standard value.

• The circuit diagram of Maxwell's inductance bridge isshown below:

We know that

Magnetic field intensity is given as:

H = I/2πr

Here I = current, r = distance

⇒ r = 15.9 m

• Solar power generation is used for power generation on small spacecraftand satellites.
• The majority of satellites are equipped with solar panels and rechargeable batteries.
• But there is a limitation to solar cells as there isno generation during eclipse periods(when the sun is blocked by the earth).
• Every year, there are short eclipses around the orbit in March and long eclipses in September.
• During eclipses, each satellite is powered by five silver-cadmium batteries.

• The DNS master file must be updated dynamically due to large number of addresses
• The Dynamic Domain Name System (DDNS) was devised for this automatic update
• In DDNS, when a binding between a name and an address is determined, the information is sent, usually by DHCP to a DNS server

Discrete fourier transform (DFT) is basically a fourier transform of “Sampled signal repeated periedically”.

The no. of points in DFT is known as N-point DFT. Which is crual to period of time domain signal.

If x[n] is sampled time domain signal, then its corresponding DFT X[k] can be expressed as:

Where N is period of x[n]

For a particular value of “k” there is (N – 1) complex addition and N complex multiplications takes place.

For one-point DFT = (N – 1) additions takes place

Then for N point DFT = (N)(N – 1) additions takes place

For one-point DFT, N multiplications takes place

Then for N point DFT, N² multiplication takes place.

Waveguides are used to direct and propagate Electromagnetic waves from one point to another. They are generally used to transmit high frequency waves such as Microwaves, Radio waves, Infrared waves etc.

The signals with high frequencies are allowed to propagate through the waveguide whereas the signals below the frequency will face a high reflection.

Waveguides are classified into two types:

1. Metal waveguides: Metal waveguides consists of enclosed conducting metal pipe and the wave guiding principle works on the total internal reflection.

2. Dielectric waveguides: These waveguides consists of dielectrics and the reflection from dielectric interfaces helps in the propagation of electromagnetic waves along the waveguide.

Metal waveguides are classified into two types:

1. Rectangular waveguides 2. Circular waveguides

A circular waveguide is a hollow metallic tube with circular cross section for propagating the electromagnetic waves by continuous reflections from the surfaces or walls of the guide.

A waveguide with a circular cross section is called as circular waveguide. It supports both Transverse electric (TE) and Transverse magnetic (TM) modes..

TM₀₁mode is preferred to TE₀₁as it requires a smaller diameter for the same cut-off wavelength.

The waveguides of circular cross section are used to transmit EM waves from one point to another.

The root values for the TM modes are:

01 = 2.405 for TM01

02 = 5.53 for TM02

11 = 3.85 for TM11

12 = 7.02 for TM12

The dominant mode for a circular waveguide is defined as the lowest order mode having the lowest root value.

The circular waveguides are perfectly symmetrical around the axis. Because of it's symmetrical nature, the dominant mode for TM waves in a circular waveguide is TM₀₁. The dominant mode TM₀₁has the lowest root value of 2.405.

conclusion: option 2 is correct

Doppler Shift:

If the observer is moving with respect to the source he observes a change in frequency of the wave emitted by the source, this is called Doppler shift or Doppler effect.

f_d = doppler frequency in Hz

v = speed of wave source (m/sec)

λ = Wavelength (m)

• The givencircuit is used to control the inching operation.
• The process ofstarting a motor with short jabs of power at reduced voltage is known as inching.
• An inching control system for an electric motor, comprising a relay having a control coil, a starting circuit, and a holding circuit.
• When the jog button is pressed, the normally open contacts energize the starter magnet. At the same time, the normally closed contacts disconnect the holding circuit.
• When the button is released, therefore, the starter immediately opens to disconnect the motor from the line.
• A jogging attachment can be used to prevent the reclosing of the normally closed contacts of the jog button.

Umbrella cell approach:

To increase the capacity of the cellular systeminstead of new cell sites additional channels and base stations can be installed. This technique is called as umbrella cell approach.

1)Umbrella cell approach is possible by using different antenna heights and different power levelsto provide small and large cells located at a single site. (statement 1 is correct)

2)This approach is used to provide large area coverage to high-speed users while small area coverage to low-speed users. (statement 2 is incorrect)

3)This approach is basically used to reduce the number of handoffs for high-speed users. (statement 3 is correct)

In electronic switching systems, the control functions are performed by a computer or a processor. Hence these systems are called Stored Program Control (SPC) systems.

New facilities can be added to a SPC system by changing the control program.

Classification of switching systems is shown below:

Attenuator :

It decreases the amplitude or any characteristics of signal.

Sample :

It samples analog signal.

Pre-alias filter :

It removes the desired component from the signal.

Modulator

A device which modulates carrier signal.

in TDM non-essential frequency components of the modulating signal are removed byPre-alias filter.

Concept:

• Anoptical time-domain reflectometer(OTDR) is anoptoelectronicinstrument used to characterize anoptical fiber.
• The Optical Time Domain Reflectometer (OTDR) is useful for testing the integrity of fiber optic cables.
• OTDR is used to verify splice loss, find faults, and measure the length of optical communication.
• The instrument emits short laserpulses, e.g. withpulse durationsofsome tens of nanoseconds andpeak powerof a few hundred milliwatts, as can be obtained with a single-modelaser diode.
• Thepulses are injected through a launchcableinto the tested opticalfiber.
• Any reflected light is extracted with a directionalfiber couplerand sent to a fast and sensitivephotodetector.
• The photodetector allows for the time-resolved measurement of the reflectedoptical powerand thus of thereturn loss.
• One can find the propagation losses and also find whether the loss coefficient is constant along with the fire or changes locally.

Concept:-

M_SSB(t) = 0.5 m(t) cos ω_ct ± 0.5 m_n(t) sin ω_ct

m_n(t) → m(t) shifted in phase by

Analysis:-

Now,

m_n(t) = sin 2π 1000 t + sin 2π 2000 t

m_SSB(t) = 0.5 (cos 2π 1000 t + cos 2π 2000 t) cos 2π 10000 t ± 0.5 (sin 2π 1000 t +sin 2π 2000 t)sin 2π 10000 t

= 0.5 [cos 2π (10000 ± 1000)t + cos 2π (10000 ± 2000)t]

∴ SSB with lower side band is given as:-

m_SSB(t) = 0.5 [cos 2π (10000 – 1000)t + cos 2π (10000 – 2000)t]

= 0.5[cos 2π 9000 t + cos 2π 8000 t]

∴ The frequencies present in lower side band are ± 8000 Hz and ± 9000 Hz.

Similarly, frequencies in upper side band is ± 11000 Hz and ± 12000 Hz

MOSFET:

• The Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is one type of FET transistor.
• In these transistors, the gate terminal is electrically insulated from the current-carrying channel so that it is also called Insulated Gate FET (IG-FET).
• Due to the insulation between gate and source terminals, the input resistance of MOSFET isvery high.
• Like JFET, the MOSFET also acts as a voltage-controlled resistor when no current flows into the gate terminal.
• The small voltage at the gate terminal controls the current flow through the channel between the source and drain terminals.
• MOSFETs also have three terminals, namely Drain (D), Source (S), and Gate (G), and also one more (optional) terminal called substrate or Body (B). MOSFETs are also available in both types, N-channel (NMOS) and P-channel (PMOS).

MOSFETs are basically classified into two forms

• Depletion Type
• Enhancement Type

Depletion Type:

• The depletion type MOSFET transistor is equivalent to a “normally closed” switch.
• So in depletion type mode,MOSFET is ina turned-onstate.
• The depletion type of transistors requires gate-source voltage (VGS) to switch OFF the device.
• The symbols for the depletion mode of MOSFETs in both N-channel and P-channel types are shown below

• The above symbols showthat the fourth terminal (substrate) is connected to the ground, but in discrete MOSFETs, it is connected to the source terminal. The continuous thick line connected between the drain and source terminal represents the depletion type.
• The arrow symbol indicates the type of channels, such as N-channel or P-channel.
• In this type of MOSFET, a thin layer of silicon is deposited below the gate terminal.
• The depletion-mode MOSFET transistors are generally ON at zero gate-source voltage (VGS).
• The conductivity of the channel in depletion MOSFETs is less compared to the enhancement type of MOSFETs.

Enhancement Type:

• The Enhancement mode MOSFET is equivalent to a “Normally Open” switch.
• So in Enhancementtype mode, MOSFET would bein a turned-offstate.
• These types of transistors require a gate-source voltage to switch ON the device.
• The symbols of both N-channel and P-channel enhancement mode MOSFETs are shown below.

• Herea broken line is connected between the source and drain, which represents the enhancement mode type.
• In enhancement mode MOSFETs, the conductivity increases by increasing the oxide layer, which adds the carriers to the channel.
• Generally, this oxide layer is called as ‘Inversion layer’.
• The channel is formed between the drain and source in the opposite type to the substrate, such as N-channel is made with a P-type substrate and P-channel is made with an N-type substrate.
• The conductivity of the channel due to electrons or holes depends on N-type or P-type channel respectively.

The correct answer is option 4.

Concept:

The second generation of GSM-based mobile networks is known as 2G. The 1G network utilized analogue radio transmissions, whereas the 2G networks used digital radio frequencies. Multiplexing was used to attain 2G capabilities by enabling numerous users on a single channel. Cell phones were utilized for data as well as voice during the 2G era.

The following were some of the important aspects of 2G:

• Data transfer rates of up to 64 kbps are possible.
• Instead of analogue signals, digital signals are used.
• SMS and MMS are examples of enabled services (Multimedia messages)
• Voice calls were of higher quality.
• It had a 30 to 200 kHz bandwidth.
• ItSupports text.
• Better quality compared to 1G.

1G Vs 2G Vs 3G Vs 4G Vs 5G:

Hence the correct answer isAll of the above.

Bilinear Transformation:

After the frequency scaling and transformation into a desirable type of filter have been performed, it is necessary to transform the resulting analog filter into a digital one.

Analog filter is stable if the poles of the transfer function are located in the left half of s plane, whereas digital filter is stable if the poles are located within the unit circle.

For this reason, the transformation must provide that the left half of s plane coincides with the area within the unit circle of z plane, as shown:

One of the most commonly used methods of transforming analog filters into appropriate IIR filters is known as bilinear transformation. It is defined via expression:

• In Bilinear Transformation, we carry out conformal mapping in which the jΩ axis is mapped onto the unit circle in the ‘z’ plane. This is a one-to-one mapping that does not bring along with it the issue ofaliasing.
• All points in the left-hand side of the s-plane get mapped inside the unit circle in the z-plane. And all points in the right-hand side of the s-plane get mapped outside the circle in the z-plane.
• First, we will transform an analog filter, get H(z), and then get a relationship between s and z.

The correct answer is1024 megabytes.

Key Points

• 1gigabyte = 2³⁰bytes = 2¹⁰×2²⁰bytes
• Since 1 megabyte =220bytes
• 1gigabyte = 2¹⁰× megabytes
• 1gigabyte =1024 megabytes
• Therefore option 3 is correct.

Important Points

• The smallest unit of memory is called abit.
• Bit stands for binary digit.
• The memory of a computer is measured inBytes
• The storage capacity of a hard disk is measured in Megabytes,Gigabytes, and Terabytes.

Additional Information

Memory Size is as follows:

A flux meteris used in electromagnet damping.

Torque in measuring instruments

Following are the types of torque produced in measuring instruments.

1.) Deflecting torque

• Thistorque causes the pointer to move from its initial (zero) position.
• To obtain this force in an instrument, different effects of electric current are used such as magnetic effect, heating effect, chemical effect, etc.

2.) Controlling torque

• The controlling force always acts in opposite direction to the deflecting force.
• This torque returns the pointer to its initial zero position when the instrument is disconnected from the supply.
• The controlling force could be produced by spring or gravity control.

3.) Damping torque

• This torqueis necessary to bring the pointer to rest in its final deflected position quickly.
• Without such damping, the combination of deflecting torque and controlling torque makes the pointer oscillate about its final deflected position for some time.
• The methods to produce damping torque in different instruments are:

The correct answer is option 2.

Concept:

Registers are a type of computer memory used to quickly accept, store, and transfer data and instructions that are being used immediately by the CPU. The registers used by the CPU are often termed Processor registers.

A list of some of the most frequent registers found in a basic computer follows:

Hence the correct answer is PC.

Torque in measuring instruments

Following are the types of torque produced in measuring instruments.

1.) Deflecting torque

• Thistorque causes the pointer to move from its initial (zero) position.
• To obtain this force in an instrument, different effects of electric current are used such as magnetic effect, heating effect, chemical effect, etc.

2.) Controlling torque

• The controlling force always acts in opposite direction to the deflecting force.
• In absence of controlling torque, the pointer will swing beyond its final steady-state position and the deflection will be indefinite.
• After the removal of the moving mechanism, the pointer has to come back to its initial position, but in absence of controlling torque, the pointer won't come back to its initial position.
• The controlling force could be produced by spring or gravity control.

3.) Damping torque

• This torqueis necessary to bring the pointer to rest in its final deflected position quickly.
• Without such damping, the combination of deflecting torque and controlling torque makes the pointer oscillate about its final deflected position for some time.
• The methods to produce damping torque in different instruments are:

Doping:

• Doping is added to an intrinsic semiconductor to form an extrinsic semiconductor.
• For p-type doped materials are Galium, Indium, Aluminium and Boron.
• For n-type materials Phosphorous, arsenic, Antimony and Bismuth.
• For p-type doping holes increases and electrons decreases.
• For n-type doping electrons increases and holes decreases.

The correct answer is Secondary memory.

Key Points

• An address bus is a computer architecture that is used to transfer data between devices that are identified by the physical address which is in binary form.
• Secondary memory in the computer provides ample storage to store a maximum number of files, videos etc. It saves the data permanently.
• The system bus in the computer is divided into the address bus andthe data bus.
• The address bus is used to specify a physical address in the memory. A data bus is used to transmit data among components.
• Secondary memory is independent of the address bus. Hence option 4 is correct.

Additional Information

• The main memory or primary memory stores the data temporarily i.e., data will be lost if there is any power outage. It is volatile.
• Cache memory and registers areexamples of primary memory. The cache is the fastest and smallest memory in the computer system.
• Cache memory contains the frequently requested data and recently visited data so that it is immediately available to the CPU when needed.

Non-Maskable interrupts.

An interrupt that cannot be ignored or disabled by the instructions of the CPU is called as Non-Maskable interrupts

It requires the processor to process them immediately.

Example: Trap of 8085

Maskable interrupt:

The hardware interrupts which can be delayed when a much high priority interrupt has occurred at the same time is called a maskable interrupt.

Concept:

Lockout free condition: If a counter from an unused state enters one of the used states then the counter is called lock-out free. While taking any unused state as the initial state if the next state comes out to be a used state, the counter is said to be lockout free.

Synchronous counter: A counter in which all the flip-flops are triggered with the same clock pulse. In such counters, if the propagation delay of one flip-flop is tf, then the propagation delay for the whole counter will also be tf

Asynchronous counter: A counter in which all the flip flops are not triggered by the same clock pulse. In such counters, total propagation delay will be equal to the sum of propagation delay for all flip flops.

Calculation:

Given that, propagation delay of each flip-flop = 40 ns

Width of the strobe pulse = 20 ns

Total propagation delay = 40 × 4 + 20 = 180 ns

Maximum clock frequency

CONCEPT:

• Potentiometer:The instrument designs for measuring the unknown voltage by comparing it with the known voltage, such type of instrument is known as the potentiometer.
• In other words, the potentiometer is the three-terminal device used for measuring the potential differences by manually varying the resistance. The known voltage is drawn by the cell or any other supply sources.

CHARACTERISTICS OF POTENTIOMETER

• The potentiometer is very accurate because it works on the comparing method rather than the deflection pointer method for determining the unknown voltages.
• It measures the null or balance point which does not require power for the measurement.
• The working of the potentiometer is free from the source resistance because no current flows through the potentiometer when it is balanced.

WORKING OF POTENTIOMETER

• The working principle of the potentiometer is explained through the circuit shown below.
• consider S is the switch used for connecting or disconnecting the galvanometer from the potentiometer.
• The battery through the rheostat and slide wire supply the working current.
• The working current may vary by changing the setting of the rheostat.

• The method of findings the unknown voltage depends on the sliding position of the contact at which the galvanometer shows the zero deflection.
• The Zero ornull deflection of galvanometer shows that the potential of the unknown source E and the voltage drops E1across the sliding wires are equal. Thus the potential of the unknown voltage drops across the ac portion of the sliding wire.
• The slide wire has the uniform cross-section and resistance across the entire length. As the resistance of the sliding wire is known, then it is easily controlled by adjusting the working current.
• The process of equalising the working voltage drop is known as the standardization.

Explanation:

A galvanometer can be converted into a voltmeter by connecting a large resistance in series with it.

The correct phrasal verb with verb ‘stem’ is ‘stem from’.

Stem from: to be caused by (something or someone).

Ex: Most of her health problems stem from an accident she had when she was five.

Hence, option A is correct.

After looking at the given parts P, Q, R, and S, it can be concluded that the correct order will be:

When he → heard the hue and cry at midnight → he was nervous and → did not know →what to do.

So, correct order is RQPS.

The correct answer is "Both A & B".

Key Points

There are two ways to escape the presentation mode, while presenting a google slide:

1) Press the ESC key from the keyboard:

• To exit presentation mode, pressEscape key from the keyboard.

2) Exit at the bottom of the slide:

• While presenting the slidespress the bottom left corner we have the three dots click on that.

• After that click on the stop presenting mode.

The correct answer is option 4.

Key Points

• Control Unit:
  • This unit controls theoperationof all parts of thecomputer but does notactually performany data processing operations.
  • Itcontrolsthe transfer of data and instructionsbetweenother units ofthecomputer.
• CPU:
  • Manyadministratorsusethe terms "CPU"and "microprocessor" interchangeably, butin reality,a CPU is essentially a microprocessor,althoughnot all microprocessors are CPUs.
• Flatbed Scanner:
  • A flatbed scanner is an optical scanner that uses a flat surface to scan documents.
  • The scanner can capture every element on the document, no need to move the document

The correct answer isOMR.

Important Points

• Optical mark recognition
  • It is the input device used to scan a marked answer book of a multiple choice question paper.
  • An optical answer sheet or bubble sheet is a special type of form used in multiple-choice question examinations.
  • Optical mark recognitionis used to detect answers.

Additional Information

• OCR
  • ​OCR(Optical Character Recognition) recognizes all the characters from the paper document.
  • Itcollects and stores them into an editable document.
• ​MICR
  • ​The term magnetic ink character recognition (MICR) refers to the line of numbers that appears at the bottom of a check.
  • TheMICRline is a group of three numbers, which are the check number, account number, and bank routing number.
• Card reader
  • A card reader is a data input device that reads data from a card-shapedstoragemedium.

The correct option is (2) ".wav and mid files"

Key Points

• The following sound effects are available for Microsoft PowerPoint: A PowerPoint presentation uses wave files and MIDI files (. wav files and. mid files).
• All popular sound file formats, including MP3, WAV, FLAC, MIDI, and WMA, are supported by PowerPoint.
• The IBM and Microsoft-developed Waveform Audio File Format (WAVE, or WAV due to its filename extension; pronounced "wave") is a standard audio file format for storing an audio bitstream on PCs.
• The Musical Instrument Digital Interface (MIDI) standard was created for digital music synthesizers and is used to transmit and store music. Recorded sounds cannot be transmitted using MIDI.

Additional InformationGIF Files:-Graphics Interchange Format is referred to as GIF. GIF is a raster file format made for simple graphics that are primarily found online.

JPEG Files:-Joint Photographic Experts Group is referred to as JPEG. One of the most popular image file formats in use today is the JPEG format.

The correct answer is MergeCells.

Key Points

• First, use the Layout tab to access the Merge Cells button.
• Second, use the Merge cells option found on the context menu when you right-click on the selected table cells.
• This will allow you to quickly access the Merge cells option.

Additional Information

• Distributed Rows
  • Select the rows that you want to affect.
  • Choose the Layout tab on the ribbon.
  • Click the Distribute Rows tool, in the Cell Size group.

• Erase table lines by using the Eraser button.
  • To do this, click the “Layout” tab of the “Table Tools”. contextual tab in the Ribbon. Then click the “Eraser” button in the “Draw” button group.
  • After clicking this button, your mouse pointer turns into an eraser when you hold it over the document.

The correct option is (1)= A1 + A2

Key Points

• In a spreadsheet, the right formula to add two values in cells A1 and A2 are =A1+A2. The SUM function in a spreadsheet is in charge of adding values.
• This means that the selected cell will contain the same value as the outcome of the specified calculation. When you click in a cell and type =A1+A2, for instance, the value of the cell you selected will be equal to the sum of the values in cells A1 and A2.
• To total the numbers, choose a cell next to them, choose AutoSum from the Home menu, and then press Enter. Excel automatically enters a formula (using the SUM function) to sum the numbers when you click AutoSum.

Additional Information

• The Functions Library in Excel has over 475 formulas, ranging from basic mathematical operations to extremely difficult statistical, logical, and engineering tasks like IF statements (one of our all-time favorite tales); AND, OR, NOT functions; COUNT, AVERAGE, and MIN/MAX.
• To perform mathematical computations, an Excel formula is utilised. The equal sign (=) and your calculation are always typed in the cell at the beginning of a formula. Calculations can be performed using formulas like =1+1 and =2*2.

The correct answer isInkjet printer.

• Non-impact printers print the characters without using ribbons. These printers print a complete page at a time so they are also called page printers.
  • E.g. Ink-Jet printer, Laser printer etc.

Additional Information

• The impact printers print the characters by striking them on the ribbon which is then pressed on the paper.
  • E.g. Drum printer, chain printer, Dot matrix printeretc.

The correct answer is Italic.

Key Points

• Ctrl + I is used to apply theitalic formatto the selected text. Hence, Option 3 is correct.

Additional Information

• List of Computer Shortcut Keys

The correct option is (2)

It converts data into digital form.

Key Points

• An output device is a piece of machinery or hardware that, after processing input data, outputs the processed data. such as a printer, a monitor, etc.
• A printer produces data from a computer, making it an output device.
• All data that a computer or other electronic device processes and sends out is referred to as output. Anything that can be seen on your computer's monitor, such as the text you write on the keyboard, is an example of the output.
• The output, which might take the form of text on a screen, printed materials, or sound coming from a speaker, is how the computer displays the outcomes of the operation.
• The system's inputs are the signals or data it receives, and its outputs are the signals or data it sends. As part of an action, the phrase can also be employed; for example, to "perform I/O" is to carry out an input or output operation.

The correct answer isF12.

Key Points

• Save the current document: Press Ctrl + S to save the current document immediately.
• Open the Save As window: Press F12 to open the Save As dialog box to save the document with a specific filename or in a new folder.
• F8 -Toggles whether to extend a selection with the arrow keys.
• F9 -Updates all the field codes in the current selection.
• F10 -Toggles the display of the ribbon shortcut keys otherwise known as Access Keys.

Additional Information

Important Shortcut keys used in MS Word:

• Cut the selected content to the Clipboard - Ctrl+X.
• Copy the selected content to the Clipboard - Ctrl+C.
• Paste the contents of the Clipboard -Ctrl+V.
• Increase the font size by 1 point.- Ctrl+].
• Center the text -Ctrl+E.
• Align the text to the left -Ctrl+L .

The correct answer isBookmark.

• A Chrome Internet browser, a method of saving web page addresses for quick access isBookmark.

Key Points

• Bookmark
  • “Bookmark”refers to links to sites that we store for easy access later.
  • Abookmarkis a saved shortcut that directs your browser to a specific webpage.
  • It stores the title, URL, and favicon of the corresponding page.
  • Savingbookmarksallows you to easily access your favourite locations on the Web.

Additional Information

• Proxy Setting
  • ​A proxy server acts as a gateway between you and the internet.
  • It’s an intermediary server separating end users from the websites they browse.
• Clear Cache
  • When weusea browser it saves some information from websites in itscacheand cookies.
  • Clearingthem fixes certain problems, like loading or formatting issues on sites.
• Delete history
  • Windows short cut to delete history:
    • CTRL+SHIFT+DEL

1st term = 3 * 1 = 3
2nd term = 3 * 3 = 9
3rd term = 3 * 9 = 27
4th term = 3 * 27 = 81

Thus, Missing number is 5th term = 3 * 81 = 243

The pattern followed here is:

Hence, the correct answer is "L".

International Yoga Day is celebrated on 21^st June every year.

Similarly;

Kargil Victory day iscommemorated on 26^th July every year.

Hence, "Kargil Victory Day : 26^th July" is the correct answer.

Important Points

Hence, "Printer" is the correct answer.

Important PointsInput Device:A piece of equipment/hardware that helps us enter data into a computer is called an input device. For example keyboard, mouse, etc.

1. Keyboard:

• A simple device comprising keys and each key denotes either an alphabet, number, or number commands which can be given to a computer for various actions to be performed
• It has a modified version of typewriter keys
• The keyboard is an essential input device and computers and laptops both use keyboards to give commands to the computer

2. Joy Stick:

• It is a device that comprises a stick that is attached at an angle to the base so that it can be moved and controlled
• Mostly used to control the movement in video games
• Apart from a computer system, a joystick is also used in the co*ckpit of an aeroplane, wheelchairs, cranes, trucks, etc. to operate them well

3. Scanner:

• This device can scan images or text and convert it into a digital signal
• When we place any piece of a document on a scanner, it converts it into a digital signal and displays it on the computer screen

Output Device: A piece of equipment/hardware that gives out the result of the entered input, once it is processed (i.e. converts data from machine language to a human-understandable language), is called an output device. For example printers, monitors, etc.

Printer:

• A device that makes a copy of the pictorial or textual content, usually over a paper is called a printer
• For example, an author types the entire book on his/her computer and later gets a printout of it, which is in the form of paper and is later published
• Multiple types of printers are also available in the market, which can serve different purposes

The sequence is a combination of two series:

I.19, 38, 114, (____)
II.2, 3, 4

Considering Series I:
1st term = 19
2nd term = 19*2 = 38
3rd term = 38*3 = 114
Thus, the missing number is 4th term = 114 * 4 = 456

i)Rohit walked 30m towards South.
ii) Took a left turn and walked 50m
iii) Again he took a left turn and walked 30m.
Drawing the Diagram as per the given information:

AB = CD = 50m
Thus we can see he is 50m far from the starting point.
Hence, the correct answer is "50m".

Given:

The side of the square = 22 cm

Formula used:

The perimeter of the square = 4× a (Where a = Side of the square)

The circumference of the circle = 2×π× r (Where r = The radius of the circle)

Calculation:

Let us assume the radius of the circle be r

⇒ The perimeter of the square = 4× 22 = 88 cm

⇒ The circumference of the circle = 2×π× r

⇒ 88 = 2× (22/7)× r

⇒

⇒ r = 14 cm

∴ The required result will be 14 cm.

As, 123 → 13²

As, 235 → 25³

The middle digit of first term becomes power to the next term.

Checking → statement I:

References:

Point A is 3km north of library.

Point C is 3km North of Point B.

Point D is 3km East of point C.

Inferences:

From the above references, we can conclude that instruction about college is missing in statement I.

So, we can’t determine the direction between library and college.

Thus, statement I alone is not sufficient to answer the question

Checking → Statement II:

References:

College is 7km North of point F.

Point D is 6km North of point E.

Library is 7km west of point E.

Point F is 4km East of point E.

Inferences:

From the above references, we can conclude the following.

We can conclude that library is to the South West direction with respect to college.

Thus, statement II alone is sufficient to answer the question.

Hence, option B is correct.

Given:

x + y + 1 = 0

Concept Used:

(a + b )³ = a³ + b³ + 3ab (a + b)

Calculations:

x + y + 1 = 0

⇒ x + y = -1

Cubing on both sides we get

(x + y)³ = ( -1 )³

⇒ x³ + y³ + 3xy( x + y ) = -1

⇒ x³ + y³ + 3xy ( -1) = -1

∵ x + y = -1

⇒ x³ + y³ - 3xy = -1

∴ required value = -1

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