PSU Sample Paper 1
Multiple choice Questions
1. The velocity of sound is the least in which of the following medium:
1) Air 2) Water 3) Wood 4) Vacuum
2. Two amplifier stages have voltage gains of 100 and 200. The total decibel voltage gain of the cascaded amplifiers is:
1) 46 dB 2) 86 dB 3) 66 dB 4) 106 dB
3. In the circuit shown, what is the minimum value of RL for which the output voltage will remain constant?
1) 15 W 2) 24 W 3) 27 W 4) 45 W
4 If 1/10th of the total current is to pass through a galvanometer of resistance G W, then the shunt resistance should be:
1) G/99 W 2) G/9 W 3) G/10 W 4) Gx9 W
5
In the circuit shown, each condenser has a capacitance of 1mF. The equivalent capacitance between P and Q is:
1) 3 mF 2) 6 mF 3) 1 mF 4) 1/3 mF
6. In an electric circuit, the applied voltage is E=100 Sin (314t) V and the resultant current is I = 5 Sin (314t + p/3). Then, the circuit is comprised of:
1) L and C 2) L only 3) R and C 4) R and L
7 At any frequency much higher than the resonant frequency of a series resonance circuit, the angle of impedance Z approaches:
1) -90° 2) +90° 3) 0° 4) 180°
8. An indirectly heated pentode has how many pins?
1) 5 2) 6 3) 7 4) 8
9 The binary number that follows 0110 1111 is:
1) 0110 1100 2) 0111 0000 3) 0111 1000 4) 0110 1110
10. A transformer has an iron loss of 300 W and full load copper loss of 1200 W. At what percentage of full load does the efficiency become maximum?
1) 80% 2) 60% 3) 50% 4) 25%
11 In a three phase, four wire circuit, the line currents in the R, Y and B phases are 1, 2 and 1 A respectively. What is the current in the neutral conductor?
1) 1 A 2) 2 A 3) 3 A 4) 4 A
12 A FM transmitter operating at 104 MHz is modulated with 5 kHz tone and the maximum deviation is 75 kHz. Total bandwidth occupied by the FM transmitter will be:
1) 150 kHz 2) 160 kHz 3) 170 kHz 4) None of these
13. What is the aspect ratio in conventional Television?
1) 2:1 2) 3:2 3) 4:3 4) 5:4
14 What is the type of modulation adopted for the Chrominance signal in TV?
1) Amplitude modulation 2) Frequency modulation
3) Phase modulation 4) Quadrature Amplitude modulation
15. A 10 kW transmitter is connected to an antenna and the reflection coefficient observed on the transmission line is 0.6. The power radiated by the antenna is:
1) 10 kW 2) 3.6 kW 3) 6.4 kW 4) None of these
16. Transmission in short wave is characterised by the following:
1) It takes place by sky wave. 2) Propagation is by reflection from ionosphere.
3) It is subject to severe fading. 4) All of these.
17. Reception of a signal through direct wave depends upon the following:
1) Height of the transmitting antenna 2) Height of the receiving antenna
3) Distance between the transmitter and receiver 4) All the above
18. Which of the following diodes exhibits negative resistance phenomenon?
1) Zener Diode 2) Ordinary Diode 3) Tunnel Diode 4) PIN Diode
19. Which has the longest wave length?
1) Microwave 2) X-ray 3) Ultraviolet ray 4) Infrared ray
20. An infinite line of characteristic impedance Zo is terminated by an impedance ZL. What is its input impedance?
1) Infinity 2) Zo 3) ZL 4) (Zo.ZL)1/2
Answers of the above problems : PSU Sample Paper 1
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