Question

In R-L-C series circuit, the potential difference across each element is 20 V. Now the value of hte resistance alone is doubled, then PD across R, L and C respectively.
A. 20 V, 10 V , 10V
B. 20 V, 20 V, 20V
C. 20 V, 40 V, 40 V
D. 10 V, 20 V, 20 V

Answer 1

Correct Answer - A
Given, the potential difference across each element is same i.e., 20V, so the circuit is at resonance and we have
`V=V_(R)=20V`
If the value of R is doubled, then value of I reduced to half
`therefore V_(L) = V_(C) = (IX_(L))/2 = (IX_(C))/2= 20/2 = 10V`
`therefore` circuit is at resonance
and `V_(R)`=V=20V