electrical engineering solved question paper

electrical engineering solved question paper
electrical engineering Solved Question Papers

1. If the aperture of the radar antenna is doubled, then the radar range will increase by a factor of
(a)√2
(b) 2
(c) 4
(d) 16

Ans:-A


2. Match List I with List II and select the correct answer using the codes given below the lists:
List I
(Systems)
A. Satellite Communication
B. Line Carrier Telephony
C. Monophonic Broadcasting
D. Stereophonic Broadcasting
List II
(Modulation)
1. SSB
2. AM
3. SQPSKJOQPSK
4. FM
5. PM
Codes:
A B C D
(a) 3 4 1 2
(b) 1 3 5 2
(c) 2 5 1 3
(d) 3 1 2 4

Ans:-D



3. Consider the following types of machines:

1. 2-phase A. C servomotor
2. Conventional 2-phase induction motor
3. Stepper motor
4. Tacho generator
The rotors are generally of drag cup construction in the case of
(a) l, 2 and 4
(b) l and 3
(c) 3 and 4
(d) l and 4

Ans:-D

4. Consider the following statements regarding the effect of adding a pole in the open-loop transfer function on the closed-loop step response:
1. It decreases the maximum overshoot.
2. It increases the rise lime.
3. It reduces the ‘bandwidth.
Of these statements:
(a) 1, 2 and 3 are correct
(b) 1 and 2 are correct
(c) 2 and 3 are correct
(d) 1 and 3 are correct

Ans:-B





5. The first two rows of Routh’s tabulation of a fourth-order system are:
S4 1 10 5
S5 2 20
The number of roots of the system lying on the right half of s-plane is
(a) Zero
(b) 2
(c) 3
(d) 4

Ans:-C













6. A control system whose step response is —0.5 (1+ e-2t ) is cascaded to another control block whose impulse response is e-4. The transfer function of the cascaded combination is
(a) 1 / (s + 1) (s + 2)
(b) 1 / s(s+1)
(c) 1 / s(s+2)
(d) 0.5 / (s+1)(s+2)

Ans:-B


7. The error response of a second order system to a step input is obtained as
E(t) = 1.66 e-8t sin (6t + 37°) The damping ratio is
(a) 0.4
(b) 0.5
(c) 0.8
(d) 1.0

Ans:-D


8. In a linear system, an input of 5 sin ω t produces an output of 10 cos ω t. The output corresponding to input 10 cost wt will be equal to
(a) +5 sin ω t
(b) —5 sin ω t
(c) +20 sin ω t
(d) 20 sin ω t

Ans:-C



9. The resistances 100 Ω ± 5 Ω and ± 15 Ω are connected in series. If the errors are spec Wed as standard deviations, the resultant error will be
(a) ±10 Ω
(b) ±10.6 Ω
(c) ±.15.8Ω
(d) ±20 Ω

Ans:-A







10. Match List I with List II and select the correct answer using the codes given below the lists:
List I
(Parameter measured)
A. Audio frequency
B. High Q inductor
C. Dielectric loss
D. Low Q inductor
List II
(Bridge)
1. Maxwell bridge
2. Hay bridge
3. Wien bridge
4. Schering bridge
Codes:
A B C D
(a) 3 4 2 1
(b) 3 2 4 1
(c) 4 2 1 3
(d) 1 4 2 3

Ans:-A


11.. A sinusoidal waveform, when observed on an oscilloscope has peak to peak amplitude of 6 cm. If the vertical sensitivity setting c 5 V/cm, the rms value of the voltage is
(a) 10.6 V
(b) 11.1 V
(c) 12.6V
(d) 15 V

Ans:-A


12. In the two-wattmeter method of measuring power in a balanced three-phase circuit, one wattmeter shows zero and the other positive maximum. The load power factor is
(a) zero
(b) 0.5
(c) 0.866
(d) 1.0

Ans:-B



13. A 35 V dc supply is connected across a resistance of 600 in series with an unknown resistance Rx A voltmeter having a resistance of 1.2 k Ω is connected across 600Ω resistance and reads 5 V. The value of resistance Rx will be
(a) 120Ω
(b) 400Ω
(c) 1.8 Ω
(d) 2.4Ω

Ans:-A

14. ‘Creep’ in energy meters can be prevented by
(a) using extra turns of the voltage coil
(b) having two holes on opposite sides of the disc
(c) using a stronger brake magnet
(d) using steel laminations of high permeability

Ans:-D

15. An integrating digital voltmeter measures
(a) true average value
(b) rms value
(c) peak value
(d) peak to peak value

Ans:-A


16. A frequency modulation wave is passed through
1. harmonic generator
2. frequency translator
The modulation index is
(a) not changed in either case
(b) changed only in1
(c) changed only in 2
(d) changed in both 1 and 2

Ans:-B


17. For high speed operation which of the folio wing parameters may have to be minimized?
1. Junction capacitance
2. Dynamic forward resistance
3. Depletion layer thickness
4. Charge storage
Choose the correct set of parameters using the codes giving below:
Codes:
(a) l and 2
(b) 1, 2 and 3
(c) l and 4
(d) 2, 3 and 4

Ans:-D


18. A MOSFET having gate-source and gate-drain capacitances as Cgs, and Cgd respectively Is connected as a CS amplifier having voltage gain = -Av The input capacitance for this amplifier is
(a) Cgs + Cgd
(b) Cgs + (l+AV) CSd
(c) Cgs (1 + Av) + Cgd
(d) Cgs — Cgd

Ans:-B


19. An R-C coupled transistor amplifier has a lower 3-dB frequency of 100 Hz due .to coupling capacitor. The emitter bypass capacitor is of such a value that the lower 3-dB frequency due to emitter degeneration alone is also 100 Hz. The lower 3-dB frequency of the stage will be
(a) 64 Hz
(b) 100 Hz
(c) 156 Hz
(d) 244 Hz

Ans:-C

20. A class B push-pull transistor amplifier is operated under optimum conditions. Vcc = 30 V, Audio Power = 4.5 watts. With the usual simplifying assumptions
(a) the DC power drawn from Vcc is 9 watts
(b) the power dissipated by each transistor is 2.25 watts
(c) the reflected resistance in the primary of the transformer is 200 ohms
(d) the peak ac collector current is 0.3 amps

Ans:-B