The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows
If the lattice constant of this semiconductor is decreased, then which of the following is correct?
All Ec, Eg, Ev decrease
All Ec, Eg, Ev increase
Ec, and Ev increase but Eg decreases
Ec, and Ev increase but Eg decreases
The circuit has two oppositely connect ideal diodes in parallel. What is the current following in the circuit?
1.33 A
1.71 A
2.00 A
2.00 A
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. The band gap in (eV) for the semiconductor is
1.1 eV
2.5 eV
0.5 eV
0.5 eV
In a common base amplifier, the phase difference between the input signal voltage and output voltage is
π/4
π
0
0
C.
0
No phase difference between input and output signal.
The thermistors are usually made of
metals with low temperature coefficient of resistivity
metals with high temperature coefficient of resistivity
metal oxides with high temperature coefficient of resistivity ‘
metal oxides with high temperature coefficient of resistivity ‘
When npn transistor is used as amplifier
electrons move from base to collector
holes move from emitter to base
electrons move from collector to base
electrons move from collector to base
For a transistor amplifier in common emitter configuration having load impedance of 1 kΩ (hfe = 50 and hoe = 25) the current gain is
-5.2
-15.7
-24.8
-24.8
A piece of copper and another of germanium are cooled from room temperature to 77 K, the resistance of
each of them increases
each of them decreases
copper decreases and germanium increases
copper decreases and germanium increases