Resonance occures in a series LCR circuit when the frequency of the applied emf is 1000 Hz.

Options

A. when f=900Hz, the circuit behaves as a capacitative circuit
B. the impedance of the circuit is maximum at f=1000 Hz
C. at resonance the voltage across L and voltage across C differ in phase by `180^(@)`
D. if the value of C is doubled resonance occurs at f=2000 Hz

Answer

A, C

Explanation

At resonance `X_(L)=X_(C) and Z=Z_(min)=R`
`X_(L)=omegaL and 1/(omegaC)=X_(C)` If 'f' is decreased then 'omega' will decrease and hence `X_(C)` will increase therefore at `f lt f_(r)` circuit behaves as capacitive
`V_(L) and V_(C)` always difference in phase by `180^(@)` at any frequency.