1 |
A diode characteristic curve is a plot between |
current and time
voltage and time
voltage and current
forward voltage and reversed voltage
|
2 |
When the pn-junction is connected reversed biased, its resistance is of the order of |
few ohms
few kilo-ohms
few mega-ohms
few mili-ohms
|
3 |
When the pn-junction is in reversed biased, current flows through the junction due to the |
majority carriers
minority carriers
either of them
none of them
|
4 |
When the pn-junction is forward biased. the current flows through it is of the order of |
mili-amperes
amperes
nano-amperes
micro-amperes
|
5 |
When the p-n junction is forward biased its resistance is of the order of |
few mega ohms
few kilo ohms
few ohms
few milli ohms
|
6 |
The value of the potential difference across the depletion region for the case of germanium is |
0.3 V
0.5 V
0.7 V
0.9 V
|
7 |
A p-n junction is formed when a crystal of silicon is growth in such a way that its one half is doped with trivalent impurity and the other half with a impurity from |
2nd group
fourth group
fifth group
sixth group
|
8 |
Average value of A.C voltage during one cycle is |
1
Zero
Maximum
Variable
|
9 |
A changing magnetic flux creates around itself |
An electromotive force
An electric field (changing electric flux)
Magnetic field
None of the above
|
10 |
When electrons in the transmitting antenna vibrate 94000 time per second, they produce radiowaves having frequency |
9.4 kHz
940 kHz
94 kHz
None of these
|
11 |
In free space, the speed of electromagnetic waves is |
3 x 10<sup>8</sup>ms<sup>-1</sup>
3 x 10<sup>6</sup>ms<sup>-1</sup>
4 x 10<sup>7</sup>ms<sup>-1</sup>
3 x 10<sup>9</sup>ms<sup>-1</sup>
|
12 |
Transmitting antenna emits |
Magnetic waves
Electric waves
Electromagnetic waves
Sound waves
|
13 |
Electromagnetic waves transmit energy equal to |
1/2 mv<sup>2</sup>
m<sub>o</sub>c<sup>2</sup>
hf/c
hf
|
14 |
Which one of the following Electro-magnetic wave have the highest frequency and shortest wave-length |
X-rays
Ultraviolet rays
y-rays
Cosmic rays
|
15 |
Chock consumes externally small |
Charge
Current
Power
Potential
|
16 |
Which one of the following waves belongs to electromagnetic spectrum |
Radio and TV waves
Radar waves
Micro waves
All of them
|
17 |
In frequency modulation (FM), the carrier waves amplitude |
Remains constant
Increase
Decreases
None of these
|
18 |
If the value of C in a series RLC circuit is increased, the resonant frequency |
Is not affected
Increase
Remains the same
Decreases
|
19 |
The phase angle of a series RLC circuit at resonance is |
180<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
None of the these
|
20 |
The total reactance of a series RLC circuit at resonance is |
zero
Equal to the resistance
Infinity
Capacitive
|
21 |
SI unit of impedance is |
hertz
henry
ampere
ohms
|
22 |
In series RC circuit when R=Xc, then the phase angle is |
0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
70<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
45<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
|
23 |
An A.C. voltage is applied across the inductor. When the frequency of the voltage is increased, the current |
Decreases
Increases
Does not change
Momentarily goes to zero
|
24 |
At resonance frequency the impedance of parallel resonance circuit is |
Maximum
Minimum
Zero
None of the above
|
25 |
The impedance of RLC series resonance circuit at resonant frequency is |
Greater than R
Equal to R
Less than R
None of these
|
26 |
An A.C. voltmeter read 250 volts. The frequency of alternating is 50 Hz, the peak value of voltage is |
3525.0 volts
35.35 volts
353.5 volts
3.535 volts
|
27 |
To design a resonant circuit of frequency 100 KHz with an inductor of inductance 5 mH, we need a capacitor of capacitance |
5.07 pF
50 pF
0.507 pF
507 pF
|
28 |
At resonance, the impedance of RLC series circuit is |
Maximum
Zero
Minimum
Determinate
|
29 |
When either L or C is increased, the resonant frequency of the RLC series circuit |
Increases
Decreases
Remains the same
Becomes zero
|
30 |
At resonance, the phase angle for RLC series resonance circuit equals |
0<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
90<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
180<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
270<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°</span>
|