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Q1. | The theoretical maximum efficiency of a half wave diode rectifier is |

A. | 0.406 [Correct Answer] |

B. | 0.5 [Wrong Answer] |

C. | 0.812 [Wrong Answer] |

D. | slightly less than 100% [Wrong Answer] |

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Explanation:-
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**Also Read Similar Questions Below :**

⇒ The method of frequency compensation in moving iron voltmeter is

to use a capacitor in series with coil

to connect a capacitor in parallel with coil

to connect a capacitor in parallel with series resistance

none of the above

⇒ In 8085 microprocessor, what is the length of status Word?

6 bits

8 bits

12 bits

16 bits

⇒ When performing numerical calculations in floating point arithmetic

- Error may occur due to finite representation of numbers.
- Error may occur due to rounding.
- Error may occur due to finite representation of inherently infinite process.

All

1 and 2 only

1 and 3 only

2 and 3 only

⇒ In liquids charge carriers are electrons only.

TRUE

FALSE

⇒ As compared to TTL, ECL has

lower power dissipation

lower propagation delay

higher propagation delay

higher noise margin

⇒ Which is not a valid dimension statement?

DIMENSION KAT(10, 20)

DIMENSION BAT (30, 20)

DIMENSION KAT(K, 10)

DIMENSION BAT (10, 5)

⇒ For generating 1 MHz frequency signal, the most suitable circuit is

phase shift oscillator

weinbridge oscillator

colpitt's oscillator

clapp oscillator

⇒ A current tracer responds to

steady current only

pulsating current only

both pulsating and steady current

none of the above

⇒ If two time varying signals of equal magnitude and zero phase displacement are applied to X and Y plates respectively; of CRO, the display will be

a straight line

a circle

an ellipse

a square

⇒ FSK is a system involving

pulse modulation

frequency modulation

amplitude modulation

phase modulation

⇒ The peak factor is the ratio of

peak and rms values

peak and average values

rms and average values

none of the above

⇒ Which of the following photodetector does not provide gain?

Phototransistor

Photoconductor

Avalanche photodiode

p-i-n photodiode

⇒ If operator '

*a*' = 1 ∠120° then (1 -

*a*) =

3

3 ∠ - 30°

3 ∠ + 30°

3 ∠60°

⇒ Parity means the same as positive or negative number.

TRUE

FALSE

⇒ A bulb rated at 60 W, 120 V is used for 30 minutes. The charge associated with this operation is

3600 C

900 C

7200 C

600 C

⇒ Which of the following 8085 instructions does not belong to arithmetic group?

`SHLD addr`

`SUI data`

`ADCM`

`INR r`

⇒ For a standard 2nd order system the maximum overshoot is 10% to an unit step input. If the magnitude of the input is doubled, then maximum overshoot and percentage of maximum overshoot is:

maximum overshoot doubles and percentage of maximum overshoot is less than double

maximum overshoot doubles and percentage of maximum overshoot do not change

maximum overshoot remain same and percentage of maximum overshoot is double

maximum overshoot more than double and percentage of maximum overshoot is less than double

⇒ When a normal atom loses an electron

the atom loses one-proton simultaneously

rest of the electrons move faster

the atom becomes a positive ion

the atom becomes a negative ion

⇒ (1001-10) is equal to

7

(8)

_{8}

(7)

_{4}

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_{4}

⇒ Debye temperature of metals is

about 10 K

about 200 K

about 600 K

about 2 K

⇒ If frames are repeated at 60 Hz and each frame has 525 lines, the time for scanning one horizontal line (for progressive scanning and no interlacing) is about

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32 μs

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0.32 μs

⇒ According to Barkhausen criteria in order to sustain the oscillations

loop gain of the circuit must be negligible

loop gain of the circuit must be equal to unity

the phase shift around the circuit must be 180°

none of the above

⇒ If B = 4 +

*j*3, (B)

^{1/3}=

2 ∠30°

2 ∠36.87°

1.71 ∠12.3°

1.71 ∠30°

⇒ Wave A starts its positive half cycle at ω

*t*= 30° and wave B starts its positive half cycle at ω

*t*= 75° then wave B is leading wave A by 45°.

TRUE

FALSE

⇒ Consider the following statements regarding electromagnetic flowmeter

- AC excitation is used to avoid polarisation of fluid.
- The meter calibration is changed as viscosity of fluid changes.
- Stainless steel pipes can be used for measuring the flow of liquid of high conductivity.

1, 2, 3 are correct

1 and 2 are correct

2 and 3 are correct

1 and 3 are correct

⇒ Negative feedback in amplifier

reduces gain

increases frequency and phase distortion

reduces bandwidth

increases noise

⇒ A microprocessor uses 3 MHz oscillator. The duration of one T state is

1 μ

*s*

0.666 μ

*s*

0.333 μ

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⇒ The multiplication of two

*n*bit numbers gives a product of length less than or equal to

*n*bits

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^{n}bits

2

*n*bits

2

^{n}- 1 bits

⇒

**Assertion (A):** Thevenin's theorem helps us to find current in a branch of a network for different values of impedances of that branch.

**Reason (R):** Thevenin's equivalent circuit replaces a network by a voltage source in series with impedance.

Both A and R are true and R is correct explanation of A

Both A and R are true and R is not the correct explanation of A

A is true but R is false

A is false but R is true

⇒ Which of the following materials has the highest electrical conductivity?

Steel

Silver

Aluminium

Zinc