NEET UG PHYSICS MCQ: ALTERNATING CURRENT

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Assertion (A)If the frequency of the applied

AC

is doubled, then the power factor of a series

R-L

circuit decreases.

Reason (R) Power factor of series R-L circuit s given' by

\cos \theta=\frac{2 {R}}{\sqrt{{R}^2+\omega^2 {~L}^2}}

View answer and explanation

Correct option: C

If Assertion is true but Reason is false.

Option C is correct because the assertion is true, but the reason is false. Increasing the frequency in an R-L circuit decreases the power factor. The correct formula for the power factor is

\cos \theta = \frac{{R}}{{\sqrt{{R^2 + (\omega L)^2}}}}

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