Physics : Semiconductor Electronics: Materials, Devices and Simple Circuits

A laser beam is used for carrying out surgery because, it

• is highly monochromatic

• is highly coherent

• is highly directional

• can be sharply focussed

The forbidden gap in the energy bands of sillicon is

• 2.6 eV

• 1.1 eV

• 0.1 eV

• 6 eV

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

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

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

Zener diode acts as a/an

• oscillator

• regulator

• rectifier

• filter

In communication with help of antenna if height is dobled then the range covered which was initially r would become

• $\sqrt{2}\mathrm{r}$

• 3r

• 4r

• 5r

In the half wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple would be

• 25 Hz

• 50 Hz

• 70.7 Hz

• 100 Hz

A transistor is a/an

• chip

• insulator

• semiconductor

• metal

The number 0 (zero) is required for

• transistor

• abacus

• computer

• calculator