IndiaBIX

Electronics and Communication Engineering - Electromagnetic Field Theory

Exercise : Electromagnetic Field Theory - Section 3
31.
The derating factor for a BJT transistor is about
0.5 mW/°C
2.5 mW/°C
10 mW/°C
25 mW/°C
Answer: Option
Explanation:

For every 1°C rise in ambient temperature the power dissipation must be reduced by 2.5 mW so that transistor is safe.

32.
An intrinsic silicon sample has 2 million free electrons. The number of holes in the sample is
2 million
almost zero
more than 2 million
less than 2 million
Answer: Option
Explanation:

In intrinsic semiconductor, the number of free electrons is equal to number of holes.

33.

Assertion (A): When reverse voltage across a p-n junction is increased, the junction capacitance decreases.

Reason (R): Capacitance of any layer is inversely proportional to thickness.

Both A and R are true and R is correct explanation of A
Both A and R are true but R is not a correct explanation of A
A is true but R is false
A is false but R is true
Answer: Option
Explanation:

Increase in reverse voltage increases the width of depletion layer and decrease of capacitance of layer.

34.
In an n type semiconductor
number of free electrons and holes are equal
number of free electrons is much greater than the number of holes
number of free electrons may be equal or less than the number of holes
number of holes is greater than the number of free electrons
Answer: Option
Explanation:

Therefore, in n type semiconductor electrons are majority carriers.

35.
Mobility of electrons and holes are equal.
True
False
Answer: Option
Explanation:

Mobility of electrons is more than that of holes.

Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers