Given below are two statements: Statement I : When the frequency of an AC source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreas

Question

Given below are two statements: Statement I : When the frequency of an AC source in a series LCR circuit increases, the current in the circuit first increases, attains a maximum value and then decreases. Statement II : In a series LCR circuit, the value of power factor at resonance is one. In the light of given statements, choose the most appropriate answer from the options given below.

TestHub · Accepted Answer

When an a.c. voltage is applied in a series LCR circuit, the current is increased first, attains a maximum and then decreases. The formula to calculate the power factor is given by

$cos ϕ = \frac{R}{R ^{2} + ( ( X _{L} ) ^{2} - ( X _{C} ) ^{2} )} ... (1)$

At resonance, $X_{L} = X_{C}$ , Hence,

$cos ϕ_{reso nan ce} = 1$

Thus, both the statements are true.

Physics - EMI/AC Question with Solution | TestHub

Options:

Doubts & Discussion