Question

In a series RL circuit, ET = 120 V, R = 40 Ω, and XL = 30 Ω. How much is EL?

Answer 1

Firstly, we will draw

RL series circuit

ET = 120 V, R = 40 Ω, and XL = 30 Ω

Firstly, we will find current

$I=\frac{E_T}{R+jX_L}$

now, we can plug values

and we get

$I=\frac{120}{40+j30}$

now, we can find voltage across L

$E_L=IjX_L$

so, we get

$E_L=\frac{120}{40+j30}(j30)$

now, we can find absolute value

$|E_L|=120\frac{30}{\sqrt{40^2+30^2} }$

$|E_L|=120\frac{30}{ 50 }$

$|E_L|=120\frac{3}{ 5 }$

$|E_L|=72V$...............Answer