1. When a inductive coil connected to a 200 V, 50Hz ac supply with 10A current flowing through it dissipates 1000 watts then which of the following will have least value in ohms
a.) Resistance b.) Reactance c.) Impedance d.) None
2. Oscillator crystal are made of
a.) Silicon b.) Germanium c.) Quartz d.) None
3. For small size, high frequency coils, the most common core material is-
a. )Air b. )Ferrite c.) Powdered ion d.) Steel
4. If we have a parallel plate capacitor of plate area 'A' and plate separatoin t and having a capacity C and a metallic plate r of area A and of negligible thickness is introduced in the capacitor at a distance from either of the two plates as shown in the given figure then the capacity of the capacitor will become
a.) b.) C c.) 2C d.) 4C
5. A superconductor is a
a.) A material showing perfect conductivity and Meissner effect below a critical temperature
b.) A conductor having zero resistance
c.) A perfect conductor with highest di-magnetic susceptibility
d.) A perfect conductor which becomes resistance when the current density through it exceeds a critical value
6. When an inductor tunes at 200 KHz with 624 pF capacitor and at 600 KHz with 60.4 pF capacitor then the self capacitance of the inductor would be
a) 8.05 pF b) 10.05pF c.) 16.01pF d.) 20.01pF
7. Sparking occur when a load is switched off because the circuit has high
a.) Inductance b.) Capacitance c.) Resistance d.) None
8. Sparking between contacts can be reduced by inserting a
a.) Resistance in the line
b.) Capacitor in series with contacts
c.) Capacitor in parallel with contacts
d.) None
9. RF amplifier of an A.M. receiver is normally biased in
a.) Class 'A' b.) Class 'b' c.) Class 'C' d.) None
10. The value of gate voltage for the operation of enhancement of only N channel MOSFET has to be
a.) High positive b.) High negative c.) Low positive d.) Zero
11. The input gate current of a FET is
a.) a few microamperes b.) negligibly small c.) a few milliamperes
d.) a few amperes
12. In the following fig. with R = 30k, the value of current through 2 K resistor is
a.) 25 mA b.) 40 mA c.) 25/16 mA d.) 10 mA
13. A step recovery diode
a.) has on extremely short recovery time
b.) conducts equally well in both directions
c.) is mainly used as a harmonic generator
d.) is an ideal rectifiers of high frequency signals
14. In order to get maximum undistorted output signal from CE amplifier with VCC 10V, the value of VCE (Q) should be approximately
a.) 0.1V b.) 5V c.) 10V d) V
15. In a FET the electrode, which corresponds to collector in bipolar transistor, is
a.) source b.) drain c.) gate d.) none
16. The device which acts like an NPN and a PNP transistor connected base to base and emitter to collector is
a.) Triac b.) UJT c.) Diac d.) SCR
17. A typical optical fibre has
a.) High refractive index core and low refractive index cladding
b.) Low refractive index core and high refractive index cladding
c.) Both a and b d.) None
18. In the following figure circuit diagram of an op-amp based is shown. The ratio is equal to
1. When a inductive coil connected to a 200 V, 50Hz ac supply with 10A current flowing through it dissipates 1000 watts then which of the following will have least value in ohms
a.) Resistance b.) Reactance c.) Impedance d.) None
2. Oscillator crystal are made of
a.) Silicon b.) Germanium c.) Quartz d.) None
3. For small size, high frequency coils, the most common core material is-
a. )Air b. )Ferrite c.) Powdered ion d.) Steel
4. If we have a parallel plate capacitor of plate area 'A' and plate separatoin t and having a capacity C and a metallic plate r of area A and of negligible thickness is introduced in the capacitor at a distance from either of the two plates as shown in the given figure then the capacity of the capacitor will become
a.) b.) C c.) 2C d.) 4C
5. A superconductor is a
a.) A material showing perfect conductivity and Meissner effect below a critical temperature
b.) A conductor having zero resistance
c.) A perfect conductor with highest di-magnetic susceptibility
d.) A perfect conductor which becomes resistance when the current density through it exceeds a critical value
6. When an inductor tunes at 200 KHz with 624 pF capacitor and at 600 KHz with 60.4 pF capacitor then the self capacitance of the inductor would be
a) 8.05 pF b) 10.05pF c.) 16.01pF d.) 20.01pF
7. Sparking occur when a load is switched off because the circuit has high
a.) Inductance b.) Capacitance c.) Resistance d.) None
8. Sparking between contacts can be reduced by inserting a
a.) Resistance in the line
b.) Capacitor in series with contacts
c.) Capacitor in parallel with contacts
d.) None
9. RF amplifier of an A.M. receiver is normally biased in
a.) Class 'A' b.) Class 'b' c.) Class 'C' d.) None
10. The value of gate voltage for the operation of enhancement of only N channel MOSFET has to be
a.) High positive b.) High negative c.) Low positive d.) Zero
11. The input gate current of a FET is
a.) a few microamperes b.) negligibly small c.) a few milliamperes
d.) a few amperes
12. In the following fig. with R = 30k, the value of current through 2 K resistor is
a.) 25 mA b.) 40 mA c.) 25/16 mA d.) 10 mA
13. A step recovery diode
a.) has on extremely short recovery time
b.) conducts equally well in both directions
c.) is mainly used as a harmonic generator
d.) is an ideal rectifiers of high frequency signals
14. In order to get maximum undistorted output signal from CE amplifier with VCC 10V, the value of VCE (Q) should be approximately
a.) 0.1V b.) 5V c.) 10V d) V
15. In a FET the electrode, which corresponds to collector in bipolar transistor, is
a.) source b.) drain c.) gate d.) none
16. The device which acts like an NPN and a PNP transistor connected base to base and emitter to collector is
a.) Triac b.) UJT c.) Diac d.) SCR
17. A typical optical fibre has
a.) High refractive index core and low refractive index cladding
b.) Low refractive index core and high refractive index cladding
c.) Both a and b d.) None
18. In the following figure circuit diagram of an op-amp based is shown. The ratio is equal to
a.) 9 b.) 11 c.) 10 d.) 2119. When a loud speaker is connected across the terminals A and B of the network shown in the fig. then its impedance to obtain maximum power dissipation in it will be
a.) 3 – j1 b.) 3 + j9 c.) 7.5 + j 2.5 d.) 7.5 – j 2.5
20. In the lattice network, the value of R for the maximum power transfer to the load
a.) 5 b.) 6.5 c.) 8 d.) 9
21. For a lossy transmission line short circuited at the receiving end, the input impedance is given by (Z0 is the characteristic impedance, Ö is the propagation constant and l is the length of the line
a.) Z0 cot h Öl b.) Z0 cot Öl c.) Z0 tan h.Ö l d.) Z0 tan Öl
22. The approximate thickness of the radome wall should be
a.) l b.) l/4 c.) l/2 d.) l/8
23. A relatively permanent information is stored in
a.) ROM b.) RAM c.) PROM d.) Volatile memory
24. The rise time of the RC network shown in the given figure is approximately equal to
b.) RC c.) 2RC d.) 4RC
25. If in the network shown in the fig. initially a steady state is attained by closing the switch 's' and then if the switch is opened at t = 0, then the current i(t) through the inductor will be
a.) cos50tA b.) 2A c.) 2cos100tA d.) 2sin50tA
26. When the p network of figure – I and T-network of figure – II are equivalent then the values of R1, R2 and R3 will be respectively
a) 9W, 6W and 6W b.) 6W, 6W and 9W c.) 9W, 6W and 9W d.) 6W, 9W and 6W
27. When the impedance matrices of a two port networks are given by and , then if these two networks are connected in series then the impedance matrix of the resulting two-port network will be
d.) indeterminate
28. Joule/coulomb is the unit of
a.) Electric field potential b.) Potential c.) Charge d.) None
29. The electric field line and equipotential lines-
a.) Are parallel to each other
b.)Are one and same
c.) Cut each other orthogonally
d.)Can be inclined to each other at any angle
30. For a lossy transmission line short circuited at the receiving end, the input impedance is given by (When Z0 is the characteristic impendence g is the propagation constant and L is the length of the line
31. When two equal positive point charges are placed along X- axis at X1 and –X1 respectively then the electric field vector at a point P on the positive Y-axis will be directed
a.) In the +x direction b.) In the –x direction
c. ) In the +y direction d.) In the –y direction
32. The directions of and in TEM mode transmission line with respect to the direction of propagation are
a.) Both and are transverse to the direction of propagation
b.) is and are transverse and h has a component in the direction of propagation
c.) is entirely transverse and has a component in the direction of propagation
d.) is entirely transverse and has a component in the direction of propagation
33. The lowest TM mode in a rectangular waveguide of cross –section a x b with a>b will be
a.) TM01 b.)TE10 c.) TM112 d.)TE11
34. When a transmitter in a free space radiates a mean power of ‘p’ watts uniformly in all directions then at a distance d sufficiently far from the source in plane the electric field E should be related to p and d as
35. When a dipole antenna was radiating with some excitation in free space radiating a certain amount of the power v if then this antenna is immersed in a lake where water is non-dissipative but has a dielectric constant of 81, then the radiated power with the same excitation will be
a.) Decrease to finite non-zero value b.)Remain the same
c. )Increase d.)Decrease to zero
36. When a (75 – j40)W load is connected to a coaxial line of Z0 = 75 W at 6MHz then the load matching on the line can be accomplished by connecting-
a.) A short – circuited stub at the load
c. )A short circuited stub at a specific distance from the load
d.)none of the above
37. As compared to analog multimeters, digital multimeters are –
a.) less accurate b.) more accurate c.) equally accurate d.) none.
38. When a signal of 10 mV at 75 MHz is to be measured then which of the following instruments can be used
a.) VTVM b.) Cathode ray oscilloscope c.) Moving iron voltmeter
d.) Digital multimeter
39. Which of the following statement is true about two wattmeter method for power measurement in three phase current ?
a.) power can be measured using two wattmeter method only for star connected three phase circuits.
b.) when two meter show indentical readings, in the power factor is 0.5.
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