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1.

When a Diode is used as a half wave rectifier ....

a)

It rectifies only one half of the input AC signal

b)

It rectifies both the halves of the input AC signal

2.

Which image shows the output of a sine-wave after it has gone through a diode? (Half-wave rectified)

a)

b)

c)

d)

3.

The function of rectifier is

a)

To increase or decrease the AC voltage in a circuit

b)

Converting the AC voltage into pulse DC voltage

c)

Smooth out the ripple contained in the pulses of pulse DC voltage

d)

Maintain a constant DC voltage output across a load

4.

The number of diodes used to build a bridge rectifier

a)

1

b)

2

c)

3

d)

4

5.

The applied input a.c. power to a half-wave rectifier is 100 watts. The d.c. output power obtained is 40 watts. What is the rectification efficiency ?

a)

40%

b)

60%

c)

80%

d)

90%

6.

Efficiency of a centre tapped full wave rectifier is _________

a)

50%

b)

46%

c)

70%

d)

81.2%

7.

Each diode in half-wave and full-wave rectifiers can only conducts current in either the positive or negative half-cycles of the AC voltage supply.

a)

True

b)

False

8.

What is the type of transistor shown in the diagram below?

a)

𝑝𝑛𝑝

b)

𝑛𝑝𝑛

c)

𝑛𝑛𝑝

d)

𝑝𝑝𝑛

e)

𝑝𝑝𝑝

9.

How does a transistor affect voltage?

a)

It causes voltage to decrease

b)

It reduces large voltage changes

c)

It does not affect voltage

d)

It amplifies small voltage changes

e)

It causes the voltage to go to zero

10.

Current through the collector is ____ the current

through the base.

a)

a little smaller than

b)

a little larger than

c)

much smaller than

d)

much larger than

e)

the same as

11.

Zener diode conducts in ________________ conditions

a)

forward bias only

b)

reverse bias only

c)

both forward and reverse bias

12.

Zener diode is used in _______________ applications

a)

Voltage regulator applications

b)

Voltage storage applications

13.

We can increase the amplitude of full wave bridge rectifier by connecting ________________________ with resistor

a)

a capacitor in parallel

b)

a capacitor in series

c)

an inductor in series

14.

What electrical component is used to smooth half wave current signals?

a)

Resistor

b)

Diode

c)

Capacitor

d)

Voltage regulator

15.

In a Transistor ………………..

a)

I_E = I_C + I_B

b)

I_C = I_E + I_B

c)

I_E = I_C – I_B

d)

I_B = I_C + I_E

16.

Which terminal was heavily dopped....?

a)

Emitter

b)

Base

c)

Collector

d)

None of the above

17.

In CB configuration, the value of α is

a)

$\frac{I_C}{I_E}$

b)

$\frac{I_E}{I_B}$

c)

$\frac{I_B}{I_C}$

d)

$\frac{I_E}{I_C}$

18.

For the transistor to work as an amplifier, which of the should be the correct bias?

a)

B-E Forward Bias
C-B Reverse Bias

b)

B-E Reverse Bias
C-B Reverse Bias

c)

C-E Forward Bias
C-B Forward Bias

d)

B-E Reverse Bias
C-E Forward Bias

19.

Amplifier circuit will be in which configuration

a)

CE

b)

CB

c)

CC

d)

None

20.

What will the circuit's output be?

a)

1

b)

0

21.

Which logic gate is this?

a)

AND

b)

OR

c)

NOT

22.

A Polarizing filter is used to reduce glare on reflective surfaces including glass, windows, and water.

a)

True

b)

False

23.

The polarisation angle for a medium is 60 degree .What is the critical angle for that medium in degree.

a)

30.3

b)

35.3

c)

39

d)

40

24.

A certain monochromatic light travelling in air is incident on a glass plate at a polarising angle. Angle of refraction in glass is found to be 32 degree. The polarising angle is

a)

50

b)

40

c)

58

d)

48

25.

Two polaroids A and B are parallel. How should be a third polaroid C placed between A and B so that the intensity of the emergent light be maximum

a)

plane of C be perpendicular to A or B

b)

plane of C be parallel to A or B

c)

plane of C can be in any direction

d)

plane of C does not decide the intensity

26.

The phase difference between the output and input voltages of a CE amplifier in degree is

a)

0

b)

180

c)

90

d)

270

27.

The purpose of emitter capacitor (i.e. capacitor across RE) is to ……….

a)

Avoid voltage gain drop

b)

Forward bias the emitter

c)

Reduce noise in the amplifier

d)

None of the above

28.

A transistor oscillators must employ

a)

Possitive feedback

b)

Negative feedback

c)

Neither negative nor positive feedbacks

d)

None of the above

29.

An oscillator circuit is mainly ..... converter

a)

A.C. to A.C.

b)

D.C. to D.C.

c)

A.C. to D.C.

d)

D.C. to A.C.

30.

An inverter gates can be developed using

a)

Two diodes

b)

Resistance and capacitance

c)

Transistor

d)

Inductance and capacitance

31.

Two input exclusive NOR gate gives high output

a)

When one input is high and the other is low

b)

Only when both the inputs are low

c)

When both the inputs are the same

d)

Only when both the inputs are high

32.

What should be the phase difference between the two plane-polarized waves, vibrating at right angles to each other, to produce circularly polarized light?

a)

π/6

b)

π/2

c)

π/4

d)

π/3

33.

Sound waves can be polarized.

a)

True

b)

False

34.

Which of the following is a uniaxial crystal?

a)

Borax

b)

Mica

c)

Quartz

d)

Selenite

35.

If the phase difference between two rays is π/2 and the angle of incidence is not equal to π/4, the emergent light is __________

a)

Linearly Polarized

b)

Elliptically Polarized

c)

Circularly Polarized

d)

Non-Polarized

36.

The velocity of light in water is 2.2 X 10⁸ m/s. What is the polarizing angle of incidence?

a)

47.23^o

b)

51.02^o

c)

53.74^o

d)

65.36^o

37.

What should be the thickness of quarter-wave plate for a light of wavelength 5890 Å if µ_e = 1.553 and µ_o = 1.544?

a)

1.33 X 10^-3cm

b)

1.43 X 10^-3 cm

c)

1.53 X 10^-3 cm

d)

1.63 X 10^-3cm

38.

A tube of length 20cm containing a 10% sugar solution rotates the plane of polarization by 13.2°. What is the specific rotation of sugar solution?

a)

66°

b)

55°

c)

44°

d)

33°

39.

The angle of polarization for any medium is 60 degree, what will be critical angle for this?

a)

$\sin^{-1}\sqrt{3}$

b)

$\tan^{-1}\sqrt{3}$

c)

$\cos^{-1}\sqrt{3}$

d)

$\sin^{-1}\ \frac{1}{\sqrt{3}}$

40.

Plane polarized light is passed through a polaroid. On viewing through the polaroid we find that when the polaroid is given one complete rotation about the direction of the light, one of the following is observed

a)

The intensity of light gradually decreases to zero and remains at zero

b)

The intensity of light gradually increases to a maximum and remains at maximum

c)

There is no change in intensity

d)

The intensity of light is twice maximum and twice zero

41.

A ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster's angle φ. If μ represents the refractive index of glass with respect to air, then the angle between reflected and refracted rays is

a)

$90+\psi$

b)

$\sin^{-1}\left(\mu\cos\psi\right)$

c)

$90^{\degree}$

d)

$90^{\degree}-\sin^{-1}\left(\sin\ \frac{\psi}{\mu}\right)$

42.

Polarised glass is used in sun glasses because

a)

It reduces the light intensity to half an account of polarisation

b)

It is fashionable

c)

It has good colour

d)

t is cheaper

43.

The transverse nature of light is shown by

a)

Dispersion of light

b)

Polarisation of light

c)

Refraction of light

d)

Interference of light

44.

A calcite crystal is placed over a dot on a piece of paper and rotated, on seeing through the calcite one will be see

a)

One dot rotating about the other

b)

Two rotating dots

c)

Two stationary dots

d)

One dot

45.

When light is incident on a doubly refracting crystal, two refracted rays-ordinary ray (O-ray) and extra ordinary ray (E-ray) are produced. Then

a)

Both O-ray and E-ray are polarised perpendicular to the plane of incidence

b)

Both O-ray and E-ray are polarised in the plane of incidence

c)

E-ray is polarised perpendicular to the plane of incidence and O-ray in the plane of incidence

d)

E-ray is polarised in the plane of incidence and O-ray perpendicular to the plane of incidence

46.

Vo and VE represent the velocities, μoand μE the refractive indices of ordinary and extraordinary rays for a doubly refracting crystal. Then

a)

$V_O\ge V_E\ ,\ \ \ \mu_O\le\mu_E$ if the crystal is calcite

b)

$V_O\le V_E\ ,\ \ \ \mu_O\le\mu_E$ if the crystal is quartz

c)

$V_O\ \le V_E\ ,\ \ \ \mu_O\ge\mu_E$ if the crystal is calcite

d)

$V_O\ge V_E\ ,\ \ \ \mu_O\ge\mu_E$ if the crystal is quartz

47.

Refractive index of material is equal to tangent of polarising angle. It is called

a)

Brewster's law

b)

Lambert's law

c)

Malus's law

d)

Bragg's law

48.

A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in the figure. The current through the diode is

a)

10 mA

b)

15 mA

c)

20 mA

d)

5 mA

49.

A crystal diode has forward resistance of the order of

a)

kΩ

b)

Ω

c)

MΩ

d)

none of the above

50.

When a PN junction diode is reverse biased

a)

Electrons and holes are attracted towards each other and move towards the depletion region

b)

Electrons and holes move away from the junction depletion region

c)

Height of the potential barrier decreases

d)

No change in the current takes place

Internal

Total questions: 50

Worksheet time: 29mins

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