The minority carrier life time and diffusion constant in a semiconductor materia

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Question
The minority carrier life time and diffusion constant in a semiconductor material are respectively 100 microsecond and 100 cm²/sec. The diffusion length is
Options
A. 0.1 cm
B. 0.01 cm
C. 0.0141 cm
D. 1 cm

Correct Answer

0.1 cm

Explanation

Diffusion length =

The minority carrier life time and diffusion constant in a semiconductor material are respectively 1

.

Electronic Devices and Circuits problems

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1. Assertion (A): A p-n junction has high resistance in reverse direction.
Reason (R): When a reverse bias is applied to p-n junction, the width of depletion layer increases.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

2. Work function of oxide coated cathode is much lower than that of tungsten cathode.
Options
A. True
B. False

3. An LED has a rating of 2 V and 10 mA. It is used along with 6V battery. The range of series resistance is
Options
A. 0 to 200 ?
B. 200 - 400 ?
C. 200 ? and above
D. 400 ? and above

4. Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down.
Reason (R): High reverse voltage causes Avalanche effect.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true

5. A periodic voltage has following value for equal time intervals changing suddenly from one value to next... 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, -5, -10 etc. Then rms value of the waveform is
Options
A. 31 V
B. 32 V
C. insufficient data
D. none of these

6. As compared to an ordinary semiconductor diode, a Schottky diode
Options
A. has higher reverse saturation current
B. has higher reverse saturation current and higher cut in voltage
C. has higher reverse saturation current and lower cut in voltage
D. has lower reverse saturation current and lower cut in voltage

7. In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be
Options
A. 0.5 eV above valence band
B. 0.28 eV above valence band
C. 0.1 eV above valence band
D. below the valence band

8. The most commonly used semiconductor material is
Options
A. silicon
B. germanium
C. mixture of silicon and germanium
D. none of the above

9. Which of the following is true as regards photo emission?
Options
A. Velocity of emitted electrons is dependent on light intensity
B. Rate of photo emission is inversely proportional to light intensity
C. Maximum velocity of electron increases with decreasing wave length
D. Both holes and electrons are produced

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