Test: Electronic Devices & Circuits - 4 - Electrical Engineering (EE) MCQ

Which of these has a layer of intrinsic semiconductor?

Assertion (A): When Diode used as rectifier the reverse breakdown voltage should not be exceeded.

Reason (R): A high inverse voltage can destroy a p-n junction.

A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 k for the sample. Which one of the following is correct?

Assertion (A): In design of circuit using BJT, a derating factor is used.

Reason (R): As the ambient temperature increases, heat dissipation becomes slower.

If the drift velocity of holes under a field gradient of 100 V/m is 5m/sec. Their mobility is

In a P type silicon sample, the hole concentration is 2.25 x 10¹⁵ / cm³. If the intrinsic carrier concentration is 1.5 x 10¹⁰/ cm³ the electron concentration is

The behaviour of a JFET is similar to that of

What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?

As temperature increases the number of free electrons and holes in an intrinsic semiconductor

At room temperature kT = 0.03 eV.

Assertion (A): A JFET behaves as a resistor when V_GS < V_P.

Reason (R): When V_GS < V_P, the drain current in a JFET is almost constant.

In a reverse biased P-N junction, the current through the junction increases abruptly at

Dielectric strength of polythene is around

Resistivity of hard drawn copper is

The channel of JFET consists of

In a bipolar junction transistor a_dc = 0.98, I_CO= 2 μA and 1_B = 15 μA. The collector current I_C is

The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage that will occur on the reverse biased diode will be

Assertion (A): The forward resistance of a p-n diode is not constant.

Reason (R): The v-i characteristics of p-n diode is non-linear.

For a photoengraving the mask used is

In a varactor diode the increase in width of depletion layer results in

In given figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20ºC, V_D is found to be 700 mV. If the temperature rises to 40ºC, V_D becomes approximately equal to

The work function of a photo surface whose threshold wave length is 1200 A, will be