Physics M.C.Q (1 Marks)

The transistors provide good power amplification when they are used in

Least doped region in a transistor

In a common emitter transistor, the current gain is 80. What is the change in collector current, when the change in base current is 250 mA

Symbolic representation of photodiode is
 

In P-N junction, the barrier potential offers resistance to

A semiconductor X is made by doping a germanium crystal with arsenic (Z = 33). A second semiconductor Y is made by doping germanium with indium (Z = 49). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct

The width of forbidden gap in silicon crystal is 1.1 eV. When the crystal is converted in to a N-type semiconductor the distance of Fermi level from conduction band is

Zener diode is used as

In a PNP transistor working as a common-base amplifier, current gain is 0.96 and emitter current is 7.2 mA. The base current is

Which of the following is true

In the case of constants a and b of a transistor

A NPN transistor conducts when

In an NPN transistor the collector current is 24 mA. If 80% of electrons reach collector its base current in mA is

The emitter-base junction of a transistor is …… biased while the collector-base junction is ……. biased

An oscillator is nothing but an amplifier with

When NPN transistor is used as an amplifier

In a full wave rectifiers, input ac current has a frequency ‘n’. The output frequency of current is

If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be

The current through an ideal PN-junction shown in the following circuit diagram will be

In the diagram, the input is across the terminals A and C and the output is across the terminals B and D, then the output is

Which is the wrong statement in following sentences? A device in which P and N-type semiconductors are used is more useful then a vacuum type because

To make a PN junction conducting

If no external voltage is applied across P-N junction, there would be

No bias is applied to a P-N junction, then the current

Which one of the following statements is not correct

The correct symbol for zener diode is
 

Consider the following statements A and B and identify the correct choice of the given answers
(A) A zener diode is always connected in reverse bias
(B) The potential barrier of a PN junction lies between 0.1 to 0.3 V approximately

Zener breakdown takes place if

The diode shown in the circuit is a silicon diode. The potential difference between the points A and B will be

In order to forward bias a PN junction, the negative terminal of battery is connected to

Select the correct statement

Serious draw back of the semiconductor device is

The maximum efficiency of full wave rectifier is

Which is the correct diagram of a half-wave rectifier(a)
 

In a PN junction photo cell, the value of photo-electromotive force produced by monochromatic light is proportional to

Of the diodes shown in the following diagrams, which one is reverse biased

A crystal diode is a

Barrier potential of a P-N junction diode does not depend on

In the middle of the depletion layer of a reverse-biased PN junction, the

For the given circuit of PN-junction diode, which of the following statement is correct

In a PN-junction

The dominant mechanisms for motion of charge carriers in forward and reverse biased silicon P-N junctions are

If the two ends P and N of a P-N diode junction are joined by a wire

When the P end of P-N junction is connected to the negative terminal of the battery and the N end to the positive terminal of the battery, then the P-N junction behaves like

Function of rectifier is