Semiconductors - General Questions

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Semiconductors - General Questions

A 0.5 μF capacitor is connected across a 10 V battery. After a long time, the circuit current and voltage across capacitor will be

A.	0.5 A and 0 V
B.	0 A and 10 V
C.	20 A and 5 V
D.	0.05 A and 5 V

Answer: Option B

Explanation:

When the capacitor is fully charged, i = 0 and voltage across capacitor is equal to battery voltage.

A capacitor stores 0.15C at 5 V. Its capacitance is

A.	0.75 F
B.	0.75 μF
C.	0.03 F
D.	0.03 μF

Answer: Option C

Explanation:

Q = CV or 0.15 = C(5) or C = 0.03 F.

A series RC circuit has R = 5 Ω and C = 10 μF. The current in the circuit is 5 sin 20000t. The applied voltage is

A.	25√2 sin (20000t + 45°)
B.	25√2 sin (20000t - 45°)
C.	25√2 sin 20000t
D.	25√2 sin (20000t - 90°)

Answer: Option

Explanation:

Z = √R² + X_C² =√ 50

V = 5√50 sin(20000 t - 45°)

V = 25√2 sin(20000 t - 45°)

In an R-C series circuit excited by a voltage E, the charge across capacitor at t = 0⁺ is

A.	0
B.	CE
C.	CE (1 - e-t/RC)
D.	none of the above

Answer: Option A

Explanation:

Voltage across a capacitor cannot change instantaneously.

Z(c) for the network shown in the figure is

.The value of C and R are, respectively

A.	1/6 F and 4 Ω
B.	2/9 F and 9/2 Ω
C.	2/3 F and 1/2 Ω
D.	1/2 F and 1 Ω

Answer: Option A

Explanation:

No answer description available for this question.

Wave A = 100 sin ωt and wave B = 100 cos ωt. Then

A.	rms values of the two waves are equal
B.	rms values of A is more than that of B
C.	rms values of A is less than that of B
D.	rms values of the two waves may or may not be equal

Answer: Option A

Explanation:

Since peak values are equal, their rms values are equal irrespective of phase difference.

The drift velocity of electrons is

A.	very small as compared to speed of light
B.	equal to speed of light
C.	almost equal to speed of light
D.	half the speed of light

Answer: Option A

Explanation:

Drift velocity of electrons is very small.

The terms RMS and average values apply only to sine waves.

A.	True
B.	False

Answer: Option B

Explanation:

These terms are applicable to all waveshapes.

Semiconductors - General Questions

Semiconductors - General Questions

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