Questions and answers for exam Preparation

MCQs

Total Questions : 848 | Page 1 of 85 pages

The concentration of minority carriers in an extrinsic semiconductor under equilibrium is

Directly proportional to the doping concentration
Inversely proportional to the doping concentration
Directly proportional to the intrinsic concentration
Inversely proportional to the intrinsic concentration

Discuss Question

Answer: Option B. -> Inversely proportional to the doping concentration

For n-type p is minority carrier concentration
np = n²
np = constant Since n_i is constant
p âˆ (1/n)
Thus p is inversely proportional to n.

Question 2.

In n-well CMOS fabrication substrate is

lightly doped n-type
lightly doped p-type
heavily doped n-type
heavily doped p-type

Discuss Question

Answer: Option B. -> lightly doped p-type

Question 3.

The sheet resistance of a semiconductor is

an important characteristic of a diffused region especially when used to form diffused resistors
an undesirable parasitic element
a characteristic whose value determines the required area for a given value of integrated capacitance
a parameter whose value is important in a thin-film resistance

Discuss Question

Answer: Option A. -> an important characteristic of a diffused region especially when used to form diffused resistors

Question 4.

A MOS capacitor has oxide thickness t_ox of 50 nm. The capacitance is

101 nF/cm2
69 nF/cm2
84 nF/cm2
None of the above

Discuss Question

Answer: Option B. -> 69 nF/cm2

Question 5. In the circuit of figure the function of resistor R and diode D are

to limit the current and to protect LED against over voltage
to limit the voltage and to protect LED against over current
to limit the current and protect LED against reverse breakdown voltage
none of the above

Discuss Question

Answer: Option C. -> to limit the current and protect LED against reverse breakdown voltage
Answer: (c).to limit the current and protect LED against reverse breakdown voltage

Question 6. As per Einstein's equation, the velocity of emitted electron in photoelectric emission is given by the equation

Discuss Question

Answer: Option B. -> B
Answer: (b).B

Question 7. Two identical silicon diodes D1 and D2 are connected back to back shown in figure. The reverse saturation current Is of each diode is 10¯⁸ amps and the breakdown voltage VBr is 50 v. Evaluate the voltages VD1 and VD2 dropped across the diodes D1 and D2 assuming KT/q to be 25 m V.