A constant voltage is applied across a circuit element. If the resistance of the element is doubled, what is the effect on the power dissipated by this element? The power dissipated is reduced by a factor of 2. The power dissipated remains constant. The power dissipated is doubled. The power dissipated is quadrupled. The power dissipated is reduced by a factor of 4.

Respuesta :

Answer:

The power dissipated is reduced by a factor of 2

Explanation:

The power dissipated by a resistor is given by:

[tex]P=I^2 R[/tex]

where

I is the current

R is the resistance

by using Ohm's law, [tex]I=\frac{V}{R}[/tex], we can rewrite the previous equation in terms of the voltage applied across the resistor (V):

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

In this problem, the resistance of the element is doubled, while the voltage is kept constant. So we have [tex]R'=2R[/tex] while V remains the same; substituting into the formula, we have:

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

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