CBSE
Multiple Choice QuestionsOn applying a reverse bias to a junction diode, it:
lowers the potential barrier
raises the potential barrier
increases the majority carrier current
increases the minority carrier current
In a common base amplifier, the phase difference between the input signal voltage and the output voltage is
zero
A light of wavelength 5000 Å falls on a sensitive plate with photoelectric work function 1.90 eV. The kinetic energy of the emitted photoelectrons will be :
(Given, h = 6.62 × 10-34 Joule second)
0.1 eV
2 eV
0.581 eV
1.581
In a reverse-biased diode when the applied voltage changes by 1 V, the current is found to change by 0.5 µA. The reverse bias resistance of the diode is
2 × 105 Ω
2 × 106 Ω
200 Ω
2 Ω
The Fermi level of an intrinsic semiconductor is pinned at the centre of the bandgap. The probability of occupation of the highest electron state in valence band at room temperature will be
zero
between zero and half
half
one
An oscillator is basically an amplifier with gain
less than unity
more than unity
zero
0.5
The energy gap between the conduction band and valence band is of the order of 0.07 eV. It is a/an
insulator
conductor
semiconductor
alloy
A triode valve has an amplification factor of 20 and its plate is given a potential of 300 V. The grid voltage to reduce the plate current to zero, is
25 V
12 V
10 V
Forward bias characteristics of a p-n junction diode are used in which of the following devices?
Transistor
Tank circuit
Rectifier
All of these
The relation between amplification factor (μ), plate resistance (rp) and mutual conductance (gm) of a triode value is given by :
none of these
