- #1

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- Homework Statement
- Select the correct option.

- Relevant Equations
- Q= X/R

X=wL

P=I*I*R

My reasoning:

Initial Q factor Q

_{1}= X

_{1}/R

After doubling the frequency, reactance also doubles.

So, Q2= 2(X1)/R.

**Hence, Q factor doubles**(option a is out).

Now, since it is mentioned that the coil has high Q factor, I assumed X >> R and hence, total impedance is approximately equal to the reactance X.

So, as frequency doubles, impedance also doubles, and current is halved.

**Therefore, P decreases by 4 times.**

So, d) should be the correct option.

But the book gives a) as the correct one.

Is there a mistake in my solution or is the book wrong?