Advertisements
Advertisements
Question
When an electric field is applied across a semiconductor ______.
- electrons move from lower energy level to higher energy level in the conduction band.
- electrons move from higher energy level to lower energy level in the conduction band.
- holes in the valence band move from higher energy level to lower energy level.
- holes in the valence band move from lower energy level to higher energy level.
Options
a and b
b and c
d and a
a and c
Solution
a and c
Explanation:
In the valence band electrons are not capable of gaining energy from the external electric fields. While in the conduction band the electrons can gain energy from the external electric field.
When an electric field is applied across a semiconductor, the electrons in the conduction band (which is partially filled with electrons) get accelerated and acquire energy. They move from lower energy levels to higher energy levels. While the holes in the valence band move from higher energy level to lower energy level, where they will be having more energy.
APPEARS IN
RELATED QUESTIONS
Draw its I – V characteristics of photodiode
Find the values of rp, µ and gm of a triode operating at plate voltage 200 V and grid voltage −6. The plate characteristics are shown in the figure.
The gain factor of an amplifier in increased from 10 to 12 as the load resistance is changed from 4 kΩ to 8 kΩ. Calculate (a) the amplification factor and (b) the plate resistance.
In semiconductor physics, what is meant by:
(i) rectifier
(ii) an amplifier
(iii) an oscillator
Answer the following question.
Why photodiodes are required to operate in reverse bias? Explain.
Depletion layer in p - n junction diode consists of
Consider an npn transistor with its base-emitter junction forward biased and collector base junction reverse biased. Which of the following statements are true?
- Electrons crossover from emitter to collector.
- Holes move from base to collector.
- Electrons move from emitter to base.
- Electrons from emitter move out of base without going to the collector.
In the circuit shown in figure, when the input voltage of the base resistance is 10 V, Vbe is zero and Vce is also zero. Find the values of Ib, Ic and β.
Draw V-I characteristics of a p-n Junction diode.
Answer the following giving reasons:
A p-n junction diode is damaged by a strong current.
