# Electronics and Communication Engineering - Electronic Devices and Circuits

1.
The ratio of impurity atoms to intrinsic semiconductor atoms in an extrinsic semiconductor is about.
1 : 10
1 : 1000
1 : 100000
1 : 108
Answer: Option
Explanation:
No answer description is available. Let's discuss.

2.
To ensure that a zener diode does not get destroyed
the applied voltage should not exceed breakdown voltage
the current should not exceed rated current
the current should be less than magnitude of barrier potential
both (a) and (b)
Answer: Option
Explanation:
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3.
SCR turns of from conducting state to blocking state on
reducing gate current
reversing gate voltage
reducing anode current below holding current value
applying ac to the gate
Answer: Option
Explanation:
No answer description is available. Let's discuss.

4.
The kinetic energy of free electrons in a metal is (where k is the de-Broglie wave number of the electron)
inversely proportional to k
inversely proportional to square of k
proportional to k
proportional to the square of k
Answer: Option
Explanation:
No answer description is available. Let's discuss.

5.
The turn on time of an SCR is 5 micro second. Its trigger pulse should have
short rise time with pulse width = 2.5 μs
long rise time with pulse width = 3 μs
short rise time with pulse width = 4 μs
long rise time with pulse width = 4 μs
Answer: Option
Explanation:
No answer description is available. Let's discuss.