An alternating voltage given by
`E = 280 sin 50 pi t` is connected across a pure resistor of 40 ohm. Find frequency of source and rms current through the bulb.

Explanation

Here, `E = 280 sin 50 pi t, R = 40 Omega, v = ? I_(v) = ?`
Compare given eqn. of E with standard for
`E = E_(0) sin pi v t`
`E_(0) = 280 V, 2 pi v = 50 pi, v = (50 pi)/(2 pi) = 25 Hz`
`I_(v) = (E_(v))/(R ) = (E_(0))/(sqrt2 R) = (280)/(sqrt2 xx 40) = (280)/(56.56)`
`=4.95 A`