If a capacitor C having selectivity factor Q is scaled down in all its dimension

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Question
If a capacitor C having selectivity factor Q is scaled down in all its dimensions by a factor K without any altering the dielectric material, the new capacitor will have capacitance and selectivity as
Options
A. C,
B. , Q
C. ,
D. C, K

Correct Answer

, Q

Explanation

Since the dimension of plates is scaled down by K, the area decreases by a factor of K², the distance between plates decreases by a factor of K.

Therefore, capacitance changes to If a capacitor C having selectivity factor Q is scaled down in all its dimensions by a factor K with .

The selectivity will not be affected.

2. A single phase electric heater uses phase controlled thyristors. The firing angle is 90�. The degree of heating is
Options
A. 25% of maximum
B. 50% of maximum
C. 75% of maximum
D. none of the above

5. Assertion (A): A class C chopper can operate in first and second quadrants
Reason (R): A class B chopper operates only in second quadrant.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

9. By inserting a plate of dielectric between the plates of a parallel plate capacitor, the energy stored in the capacitor is increased five times. The dielectric constant of material is
Options
A.
B.
C. 5
D. 25

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