Question

19. Find the current in a circuit if the power is 500 W (watts) and the resistance is 25 ohms. Round off your answer to two decimal places. Use the formula .

A. 4.47 A
B. 0.22 A
C. 20 A
D. 0.05 A

Answer 1

For this case we have by definition, that the electrical power is given by:

`P = I ^ 2 * R`

Where:

P: It's the power

I: It's the current

R: It's the resistance

Clearing the current:

`I ^ 2 = \frac {P} {R}\\I = \pm \sqrt {\frac {P} {R}}`

We choose the positive value:

`I = \sqrt {\frac {500} {25}}\\I = \sqrt {20}\\I = 4.47A`

ANswer:

Option A