A constant voltage is applied across a circuit. If the resistance in the circuit is doubled, what is the effect on the power dissipated by the circuit?

a.The power dissipated is quadrupled

b.The power dissipated is reduced by a factor of 2.

c.The power dissipated is reduced by a factor of 4

d. The power dissipated is doubled.

e. The power dissipated remains constant.

Respuesta :

Answer:

b.The power dissipated is reduced by a factor of 2.

Explanation:

The power dissipated in the circuit is given by

[tex]P=\frac{V^2}{R}[/tex]

where

V is the voltage

R is the resistance

In this problem:

- The voltage V is kept constant

- The resistance is doubled, so R' = 2R

Therefore, the new power dissipated is

[tex]P'=\frac{V^2}{R'}=\frac{V^2}{2R}=\frac{1}{2}\frac{V^2}{R}=\frac{1}{2}P[/tex]

so, the power dissipated is reduced by a factor of 2.