1.The transformer utilization factor of full wave bridge rectifier is
(A) 0.812 (B) 0.286 (C) 0.693 (D) 0.782
2. When a dominant mode wave guide not terminated in its characteristic impedance is excited with a 10 GHZ signal then ifd is the distance between two successive minima of the standing wave in the guide then
(A)d = 1.5 cm (B)d is less then 1.5 cm (C)d is greater then 1.5 cm (D)d = 3cm
3. A two port network having a 6 dB loss will give
(A) an output power which is one - quarter of the input power (B) an output power which is one - half of the input power
(C) an output voltage which is 0.707 of the input voltage. (D) an output power which is 0.707 of the input power.
4. While transporting a sensitive galvanometer
(A) the terminals are kept shorted
(B) critical damping resistance is connected across the terminals
(C) the terminals are kept open circuited
(D) it does not matter as to what is connected across the terminals.
5. A T type attenuator is designed for an attenuation of 40 dB and terminating resistance of 75 ohms.
Which of the following values represent full series armR1 and shunt armR2?
1.R1 = 147 Ω 2.R1 = 153 Ω 3.R1 = 1.5 Ω 4.R1= 3750 Ω
(A) 1 and 3 (B) 1 and 4 (C) 2 and 3 (D) 2 and 4
6. For a transmission line, the characteristic impedance with inductance 0.294µH/m and capacitance 60pF/m is
(A) 49Ω (B) 60Ω (C) 70Ω (D) 140Ω
7. When the graph of a network has six branches with three tree branches then the minimum number of equations required for the solution of the network is
(A) 2 (B) 3 (C) 4 (D) 5
8. Consider the following statement for a 2-port network
3.Y12 = -Y21
4.BC - AD = -1
then the network is reciprocal if and only if
(A) 1 and 2 are correct (B) 2 and 3 are correct (C) 3 and 4 are correct (D) 4 alone is correct.
9. As a network contains only independent current sources and resistors then if the values of all resistors are doubled then the values of the node voltages are
(A) will become half (B) will remain unchanged
(C) will become double (D) cannot be determined unless the circuit configuration and the values of the resistors are known.
10. A iron cored choke is a
(A) Linear and active device (B) Non linear and passive device (C) Active device only (D) Linear device only
11. Poynting vector wattmeter is based on
(A) Seebeck effect (B) Ferranti effect (C) Induction effect (D) Hall effect
12. Which one of the following is not a transducer in the true sense?
(A) Thermocouple (B) Piezoelectric pick-up (C) Photo voltaic cell (D) LCD.
13. The term used to denote a static device that converts ac to dc, de to ac, dc to dc or ac to ac is
(A) Converter system (B) Inverter (C) Chopper (D) Thyristor
14. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt then the efficiency of the antenna is
(A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%
15. In commercial FM broadcasting, the maximum frequency deviation is normally
(A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz
16. Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is
(A)sinusoidal (B) square (C) rectangular (D) triangular
17.Strain gauge is
(A) not a transducer (B) an active transducer (C) not an electronic instrument
18. A high Q coil has
(A) large band width (B) high losses (C) low losses (D) flat response
19. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having a guaranteed accuracy of 1% full scale reading, the percentage limiting error is
(A) 1.810% (B) 0.181% (C)12.45% (D) 0.0018%
20. The 'h' parameter equivalent circuit of a junction transistor is valid for
(A) High frequency, large signal operation (B) High frequency, small signal operation (C) Low frequency, large signal operation.
21. A system is causal if the output of any time depends only on
(A) Values of input in the past and in the future (B) Values of input at that time and in the past
(C) Values of input at that time and in the future (D) none
22. Form the hot metal surface electrons escape because
(A) of change of state from metal to gas due to heat. (B) of change of state from gas to metal (C) the energy supplied is greater than the work function (D) the energy is greater than Fermi level
23. The most common device used for detection in radio receivers is
(A) amplifier (B) triode (C) diode (D) transistor
24. In a full wave rectifier the negative point in a circuit is
(A) cathode (B) anode (C) The central tap on the high voltage secondary (D) plate.
25.Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will
(A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increase the noise
(D) Not effect the noise