# Electronics and Communication Engineering - Exam Questions Papers

21.

Consider the following statements:

1. Acceptor level is formed very close to the conduction band.
2. The effective mass of the free electron is same as that of a hole.
3. The magnitude of the charge of a free electron is same as that of a hole.
Which of the above statements are correct?

 A. 1 and 3 B. 2 and 3 C. 2 and 4 D. 3 and 4

Explanation:

No answer description available for this question. Let us discuss.

22.

The following properties are associated with ferroelectric materials:

1. Its susceptibility is negative.
2. The susceptibility is expressed as where c is the Curie constant and Tc is the Curie temperature.
3. It has permanent dipoles oriented randomly.
Which of the above statements is/are correct?

 A. 1 only B. 1 and 3 C. 2 only D. 1, 2 and 3

Explanation:

No answer description available for this question. Let us discuss.

23.

Consider the following statements:
For a master-slave J-K flip-flop,

1. the toggle frequency is the maximum clock frequency at which the flip-flop will toggle reliably.
2. the data input must precede the clock triggering edge transition time by time minimum time.
3. the data input must remain fixed for a given time after, the clock triggering edge transition time for reliable operation.
4. propagation delay time is equal to the rise time and fall time of the data.
Which of the above statements is/are correct?

 A. 1, 2 and 3 B. 1 and 2 only C. 2 and 3 only D. 3 and 4 only

Explanation:

No answer description available for this question. Let us discuss.

24.

There are four different algorithms A1, A2, A3 and A4 to solve, a given problem with the complexity order log(n), log(log(n)), n log and n/log(n) respectively. Which is the best algorithm?

 A. A1 B. A2 C. A3 D. A4

Explanation:

No answer description available for this question. Let us discuss.

25.

In Quine-Mclusky method of Boolean function reduction; __________ , are treated as __________ and therefore discrepancies may occur in the final solution, therefore this method is not applicable to the functions with __________ .

 A. zeros, don't care conditions, zeros B. one's, don't care conditions, one's C. don't care conditions, zeros, don't care conditions D. don't care conditions, don't care conditions, don't care conditions