Question

In a purely resistive circuit a source of e.m.f. having e = 140 sin (3142 t) is connected across a pure resistor. If value of rms current is 1.98 A, calculate the value of resistance.

Answer 1

In a purely resistive circuit,

Given: e = 140 sin 3142 t. So, e₀ = 140 V

The value of the rms current is given as 1.98 A.

Formula: `e_"rms" = e_0/(sqrt2)`

= `140/sqrt2`

= `140/1.4142`

= 98.99 V

`i_"rms" = e_"rms"/R`

R = `e_"rms"/i_"rms"`

= `98.99/1.98`

= 49.9 ≈ 50 Ω