CBSE
Multiple Choice QuestionsAssertion: A photocell is called an electric eye.
Reason: When light is incident on some semiconductor its electrical resistance is reduced.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
A Ge specimen is doped with Al. The concentration of acceptor atoms is ∼ 1021 atoms/m3. Given that the intrinsic concentration of electron-hole pairs is 1019/m3, the concentration of the specimen is
1017/m3
1015/m3
104/m3
102/m3
A laser beam is used for carrying out surgery because, it
is highly monochromatic
is highly coherent
is highly directional
can be sharply focussed
Assertion: Diode lasers are used as optical sources in optical communication.
Reason: Diode lasers consume less energy.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: In a common-emitter amplfier, the load resistance of the output circuit is 1000 times the load resistance of the input circuit. If = 0.98, then voltage gain is 49 x 103.
Reason: ( symbols have their usual meaning ).
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Which of the following gates correspond to the truth table given below?
| A | B | Y |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
NAND
OR
XOR
NOR
In the given circuit, the potential difference between A and B is
0
5 volt
10 volt
15 volt
Assertion: Most amplifiers use common emitter circuit configuration.
Reason: Its input resistance is comparatively higher.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
The forbidden gap in the energy bands of sillicon is
2.6 eV
1.1 eV
0.1 eV
6 eV
If collector current is 120 mA and base current is 2 mA and resistance gain is 3, what is power again?
180
10800
1.8
18
