Online Electronics and Communication Engineering Test - Electronics and Communication Engineering Test - Random

Instruction:

  • This is a FREE online test. Beware of scammers who ask for money to attend this test.
  • Total number of questions: 20.
  • Time allotted: 30 minutes.
  • Each question carries 1 mark; there are no negative marks.
  • DO NOT refresh the page.
  • All the best!

Marks : 2/20


Total number of questions
20
Number of answered questions
0
Number of unanswered questions
20
Test Review : View answers and explanation for this test.

1.
A system defined by is initially at rest, and x = u(t) sin 2t then the forced response is K sin (2t - θ). The value of θ given by
-tan-1(1)
-tan-1(2)
0
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

.


2.
In figure, the current I is
1 A
2 A
4 A
8 A
Your Answer: Option
(Not Answered)
Correct Answer: Option

3.
A network has two sources of different frequencies. The only method of analysis which can be used to find current and voltages of different branches is the use of
Kirchoff's laws
Superposition theorem
Thevenin's theorem
Tellegen's theorem
Your Answer: Option
(Not Answered)
Correct Answer: Option

4.
A person with a receiver is 5 km away from the transmitter. What is the distance that this person must move further to detect at 3 dB decrease in signal strength?
942 m
2070 m
4978 m
5320 m
Your Answer: Option
(Not Answered)
Correct Answer: Option

5.
The phase velocity in a transmission line is
v = LC
v = LC
Your Answer: Option
(Not Answered)
Correct Answer: Option

6.
Mutual impedance is not depend upon
magnitude of induced current
tuning condition
self impedance
phase relationship between induced and original currents
Your Answer: Option
(Not Answered)
Correct Answer: Option

7.
An ammeter of 0-25 A range has a guaranteed accuracy of 1% of full scale reading. The current measured is 5 A. The limiting error is
2%
2.5%
4%
5%
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

.


8.
A class C amplifier has input frequency of 200 kHz. If width of collector pulses is 0.1 μs, duty cycle is
1%
2%
10%
20%
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

.


9.
The advantage of using crystal oscillator is that it
requires low d.c. supply voltage
works at high frequency
gives high output voltage
gives constant frequency of oscillations
Your Answer: Option
(Not Answered)
Correct Answer: Option

10.
In a push pull circuit the two transistors are
both pnp
both npn
one pnp and other npn
either (a) or (b)
Your Answer: Option
(Not Answered)
Correct Answer: Option

11.
ICs are
analog
digital
both analog and digital
mostly analog
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

Op-amp is an analog IC.


12.
The control logic for a binary multiplier is specified by a states diagram. The state diagram has four states and two inputs. To implement it by the sequence register and decoder method.
two flip-flop & 2 x 4 decoder are needed
four flip-flop & 2 x 4 decoder are needed
two flip-flop & 3 x 9 decoder are needed
four flip-flop & 3 x 9 decoder are needed
Your Answer: Option
(Not Answered)
Correct Answer: Option

13.
A device that converts from decimal to binary numbered is called
decoder
encoder
CPU
converter
Your Answer: Option
(Not Answered)
Correct Answer: Option

14.

Assertion (A): In control system velocity error is not an error in velocity but is an error in position due to a ramp input.

Reason (R): For a type of system velocity error is zero.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
R is correct but A is wrong
Your Answer: Option
(Not Answered)
Correct Answer: Option

15.
Which control action can never be used alone?
Proportional
Derivative
Integral
Both (b) and (c)
Your Answer: Option
(Not Answered)
Correct Answer: Option

16.
Consider the following statements about root locus
  1. The root locus is symmetrical about real axis.
  2. If a root locus branch moves along the real axis from an open loop pole to zero or to infinity, this root locus branch is called real root branch.
  3. The breakaway points of the root locus are the solutions of
Which statements out of above are correct?
1 and 2 only
1 and 3 only
1, 2 and 3
2 and 3 only
Your Answer: Option
(Not Answered)
Correct Answer: Option

17.
The path length between ports 1 and 2 for the two waves in a hybrid ring is
1
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

The quantities required to be measured in microwave circuits are frequency, power and impedance.

Microwave frequency measurement is done by slotted line, resonant cavities and transfer oscillator.

Microwave power measurement uses bolometers and microwave power meters.

A self balancing bridge working on the principle of power substitution is commonly used.

Microwave impedance measurement is done by measurement of reflection coefficient and VSWR.

A slotted line and probe is a basic tool for these measurements.' Network analyser enables rapid impedance measurement over a broad frequency range.


18.
The amplifier circuit shown below uses a silicon transistor. The capacitors Cc and CE can be assumed to be short at signal frequency and the effect of output resistance r0 can be ignored. If CE is disconnected from the circuit, which one of the following statements is TRUE?
The input resistance Ri increases and the magnitude of voltage gain Av decreases
The input resistance Ri decreases and the magnitude of voltage gain Av decreases
Both input resistance Ri and the magnitude of voltage gain Av decrease
Both input resistance Ri and the magnitude of voltage gain Av increase
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

Given circuit after removing CE will behave as current-series feedback.

Overall voltage gain will decrease as feedback signal comes into picture and since it is current-series feedback, input impedance increases.


19.
A delta modulation system is designed to operate at 3 times the Nyquist rate for a signal with a 3 KHz bandwidth. The quantization step size is 250 mv. The maximum amplitude of a 1 KHz input sinusoidal for which the delta modulator does not show slope overload is :
716.2 mV
500 mV
647.87 mV
400 mV
Your Answer: Option
(Not Answered)
Correct Answer: Option
Explanation:

.


20.
For dielectric to dielectric interface with surface charge density, which of the following statements are true?
  1. Dn2 - Dn1 = rs
  2. Et1 = Et2
  3. En1 = En2
1, 2 and 3
1, 2 and 4
1, 2 only
1, 4 only
Your Answer: Option
(Not Answered)
Correct Answer: Option

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