Question

An electric bulb is rated 200 V and 100 W. When it is operated on 100 V, the power consumed will be –



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Answer 1

Answer:

the required answer is 25 watt

QUESTION:

An electric bulb is rated 200 V and 100 W. When it is operated on 100 V, the power consumed will be ..............

TO FIND:

power consumed , P'

GIVEN:

• voltage of bulb, V= 200 V
• power of bulb, P= 100 W
• voltage supplied, V' = 100 V

FORMULA:

P=V^2/R

SOLUTION:

to find the power consumed ,first we need to find the resistance , R of the bulb.

STEP 1:

• TO FIND RESISTANCE OF BULB USING POWER OF BULB AND VOLTAGE OF BULB.

P=V^2/R

R=V^2/P

=(200)^2/100

=40000/100

R=400 ohm

STEP 2:

• TO FIND THE POWER CONSUMED USING THE RESISTANCE AND VOLTAGE SUPPLIED.

P'=V'^2/R

=(100)^2/400

=10000/400

=100/4

P'= 25 W