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## A 630 W bulb and a 315 W bulb are both designed to operate at standard household voltage of 120 V. Determine which bulb has the lower filame

Question

A 630 W bulb and a 315 W bulb are both designed to operate at standard household voltage of 120 V. Determine which bulb has the lower filament resistance and then calculate the value of its resistance.

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Physics
2 months
2021-08-21T23:09:45+00:00
2021-08-21T23:09:45+00:00 1 Answers
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## Answers ( )

Answer:630 W bulb has lower resistance than 315 W bulb

Explanation:The resistance of the bulb can be found using the operating voltage of the bulbs and their wattage.

As we know from Ohm’s law

V = IR

I = V/R

Also power is given by

P = VI

P = V*(V/R)

P = V²/R

R = V²/P

For Bulb 1:

R = 120²/630

R = 22.85 ΩFor Bulb 2:

R = 120²/315

R = 45.71 ΩTherefore, the bulb with a higher wattage of 630 W has lower resistance than the bulb with a lower wattage of 315 W.