Lightbulbs are typically rated by their power dissipation when operated at a given voltage. Which of the following lightbulbs has the larges

Question

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

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Vân Khánh 3 years 2021-08-21T13:23:01+00:00 1 Answers 28 views 0

Answers ( )

  1. Bo
    0
    2021-08-21T13:24:49+00:00
    Reply

    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

    P = \frac{V^{2} }{R}

    R = \frac{V^{2} }{P}

    a)  R = \frac{1.5^{2} }{0.8} = 2.8 Ω

    b) R = \frac{3^{2} }{6} = 1.5 Ω

    c) R = \frac{4.5^{2} }{4} 5.06 Ω

    d) R = \frac{6^{2} }{8} = 4.5 Ω

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

    C. 4 W, 4.5 V

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