A 20volts `AC` is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is `12V`, the voltage across the coil is

Options

A. `16` volts
B. `10` volts
C. `8` volts
D. `6` volts

Answer

A

Explanation

The voltage across a `L-R` combination is given by
`V^(2)=V_(R)^(2)+V_(L)^(2)`
`V_(L)=sqrt(V^(2)-V_(R)^(2))=sqrt(400-144)=sqrt(256)=16 vol t`.