RRB JE ECE (CBT II) Mock Test- 2 - Electronics and Communication Engineering (ECE) MCQ

• In the SPWM, the modulating signal is sinusoidal
• SPWM output is generated by intersection between sine signal and triangle signal
• Sine signal is the reference waveform and triangle waveform is the carrier waveform
• When value sine signal is large than triangle signal, the pulse will start produce to high

An Op-Amp should have

i) High Bandwidth

ii) High input impedance

iii) Low output impedance

iv) High Gain

v) High CMRR

vi) High slew rate

• The quantum number defines an electron completely in an atom. 
• There are four types of quantum number - Principal Quantum Number, Azimuthal Quantum Number, Magnetic Quantum Number and Spin Quantum Number. 
• Principal Quantum Number describes the size, shape and energy of the shell to which an electron belongs whereas Azimuthal Quantum Number determines the shape of the electron cloud and the number of sub-shells in a shell. 
• Magnetic Quantum Number determines the orientation of sub-shells whereas the spin quantum number represents the direction of the electron spin. 

Zener Breakdown:

In a heavily doped PN junction, under high reverse voltage (around 5 V), the electrons tunnel though the depletion region due to extremely small depletion region width.

Even though the electric field is very high the electrons are able to tunnel through due to very thin depletion regions.

This causes high reverse current to flow even in reverse bias. The junction is not destroyed can be used as normal PN diode in forward bias.

Avalanche Breakdown:

In thinly doped PN junction diodes Zener effect is not possible, but under very high reverse voltage (< 8-10 V) the high electric fields (lower than Zener diode) cause the electrons to accelerate.

The accelerated electrons break free more electrons (called impact ionization) this newly free electrons in turn create more charge carriers causing a kind of avalanche effect.

This results in huge reverse current, but the junction is destroyed to this effect.

In the lower part of the thermosphere region, between 100 and 400 km, the ionisation of the atmospheric gases takes place and the layer is called ionosphere.

The ionosphere is ionized by solar radiation.

There is a peak concentration of ionized particles at 250 kms which is responsible for the deflection of radio waves.

Delay Problem:

In asynchronous counters the output of the previous stage serves as the clock of the next stage. As the number of stages increases the propagation delay of each flip flop stage adds up and this propagation delay becomes significant.

Remedy of Propagation delay:

To eliminate the propagation delay encountered in different stages, all the flip flops are provided with a common clock. Thus, the output of each stage does not depend on the clock from the previous stage but only on the common clock signal and propagation delay does not adds.

After defeating the Portuguese, Jahangir was influenced by the British,As a result, a royal decree issued in 1613 AD gave the British permission to establish a trading kothi in Surat. Thus, in the initial period of the East India Company, the Western Presidency was in Surat.
Hence, the correct option is (A)

Let present age of Ram be x and Shyam be y 

From question, 

(x - 5) = 3(y – 5 ) => x – 3y = -10 ……. (i) 

(x+ 4 ) = 2(y + 4) => x – 2y = 4 …….. (ii) 

After solving equation (i) and (ii) we get 

x = 32 

Hence present age of Ram be 32 years 
Hence, the correct option is (B)

Segmentation is the process in which the main memory of the computer is divided into different segments and each segment has its own base address.
It is used to enhance the speed of execution of the computer system, so that processor is able to fetch and execute the data from the memory easily and fast.
Memory segmentation is shown below

Concept:

The continue statement is used inside loops.

When a continue statement is encountered inside a loop, control jumps to the beginning of the loop for next iteration, skipping the execution of statements inside the body of loop for the current iteration.

Application:

Loop can be constructed using For, while, do while statements.

When V < 10 V I = 0

For V > 10 V, diode is forward biased

Apply kVL:

V - 4I - 10 = 0

V = 4I + 10

y = mx + c

slope = m = 4

y intercept = c = 10

Since all resistance are equal let
R₁ = R₂ = R₃ = R₄ = R

V_A = 0 (Virtual ground)
Now R₂ are R₄ are in parallel, connected between node voltage at B and ground.
Equivalent: R||R = R/2


V _o / V _i = - R/3R/2 = - 2/3 = - 0.66 V

Current through 1Ω resistor is
I - V/R = 1V/1Ω = 1A
Apply KCL at Node A

I’ + 1 = 1A
I’ = 0A
Since I’ = 0 A, the power delivered by the voltage source = VI’ = OW

• For critically damped system ζ = 1.
• The response of the system in this case is rapid and the system reaches its final steady state conditions smoothly without oscillations. 

Convert gray to binary:

Copy the MSB and then Exor as shown

Step 2.

Now convert the binary to decimal

1101 → (13)₁₀

• Alkalinity refers to the capability of water to neutralize the acid
• The alkalinity of natural water is determined by the soil and bedrock through which it passes
• The main sources for natural alkalinity are rocks which contain carbonate, bicarbonate, and hydroxide compounds. Borates, silicates, and phosphates also may contribute to alkalinity

SRAM has 6 MOS transistors whereas DRAM has 1 MOS transistors and 1 capacitor.

SRAM (static RAM) is random access memory (RAM) that retains data bits in its memory as long as power is being supplied

Internal resistance of a cell: It is the resistance which is present within the battery that resists the current flow when connected to a circuit. It is the resistance offered by its electrolyte to the flow of ions. Thus, it causes a voltage drop when current flows through it.

Here E is the emf of a cell and r is the internal resistance.

Factors affecting internal resistance of a cell:

• It is directly proportional to the distance between the electrodes
• It is inversely proportional to the surface area of the electrodes dipped in electrolyte
• It is inversely proportional to the temperature of electrolytes
• It is inversely proportional to the concentration of electrolytes
• Greater the conductivity of the electrolyte, lesser is the internal resistance of the cell. i.e. internal resistance depends on the nature of the electrolyte.

Concept:

The numerical aperture is given by:

NA = n₀ sin θ_0max

Where n₀ is the refractive index of the air (surrounding)

Calculation:

The work done on a body moving in a circular path is also zero. This is because,when a body moves in a circular path, then the centripetal force acts along the radius of the circle, and it is at right angles to the motion of the body. Thus, the work done in the case of moon moving round the earth is also zero.

• A number of these pairs are bundled together into a cable by wrapping them in a tough protective sheath
• Over longer distances, cables may contain hundreds of pairs
• The twisting tends to decrease the crosstalk interference between adjacent pairs in a cable
• Neighbouring pairs in a bundle typically have somewhat different twist lengths to reduce the crosstalk interference

Master-Slave flip flop is the cascaded combination of two flip-flops among which the first is designated as master flip-flop while the next is called slave flip-flop.

The master flip-flop is triggered by the external clock pulse train while the slave is activated at its inversion i.e. if the master is positive edge-triggered, then the slave is negative-edge triggered and vice-versa.

There will be a change in the output when the state of the slave is affected because the output is taken at the slave.

The drain current in MOSFET in saturation is given by

From the equation it is evident that MOSFET’s drain current depends on:

1. Device parameters W/L
2. Gate to source Voltage V_GS

To realise this physically, as the Gate to source voltage is increased, the channel becomes deeper, hence there is more area through which electrons can move.

Various Theorem and the circuits where they are applicable is shown below in the table

Given that, deflection factor (d) = 0.5 V/m

Deflection sensitivity (s) is the reciprocal of deflection factor.

FF + 01 = 1 00 H

The accumulator contains 00 H

And 1 carry is obtained

The important point to note here that carry is obtained and this will set the carry flag.

This is the main difference between INR A and ADI 01 instruction.

percentage accuracy = measured value / expected value.100 %

percentage accuracy = 39 / 40 .100 %

= 97.5 %

Let wire be of length 1000 unit and cross area be also 1000 unit²

After stretching new length = 1.1% of 1000 = 1001

Volume is same (length x cross section)

1000 × 1000 = 1001 × A’

A’ = 1000 × 1000/1001

= 999

% change = -0.1%

R = ρ l/A

Taking log and differentiating

dR / r = dl / L - dA / A

Substituting value

dR / R x 100 = 0.1 -(-0.1) = 0.2%

Using the equation,

for the ball released from height h,

for the ball released from height 2h

The ratio of the time taken is

t / t¹ = t / √2t = 1 / √2_t