Lightbulbs are typically rated by their power dissipation when operated at a given voltage. Which of the following lightbulbs has the largest resistance when operated at the voltage for which it's rated?
A. 0.8 W, 1.5 V
B. 6 W 3 V
C. 4 W, 4.5 V
D. 8 W, 6 V

Respuesta :

Answer:

The arrangement with the greatest resistance is the light bulb of option C. 4 W, 4.5 V

Explanation:

The equation for electric power is

power P = IV

also,  I = V/R,

substituting into the equation, we have

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

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

a)  [tex]R = \frac{1.5^{2} }{0.8}[/tex] = 2.8 Ω

b) [tex]R = \frac{3^{2} }{6}[/tex] = 1.5 Ω

c) [tex]R = \frac{4.5^{2} }{4}[/tex] 5.06 Ω

d) [tex]R = \frac{6^{2} }{8}[/tex] = 4.5 Ω

from the calculations, one can see that the lightbulb with te greates resistance is

C. 4 W, 4.5 V