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Question
An electric bulb is rated ‘240 V, 100 W’.
- What information can you get from the above statement?
- What will happen if this bulb is connected across 220 V?
- Calculate the resistance of the bulb.
- Also find the energy consumed by the bulb in 10 minutes.
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Solution
a. The above statement gives the information that when the electric bulb is put at 240 V of a potential difference it consumes 100 W of power.
b. The bulb will consume less power.
c. R = `"v"^2/"p"`
`= (240 xx 240)/100`
= 576 Ω
d. Electrical energy (kWh) = kW × h
`= 100/100 xx 10/60`
`= 1/60` kWh
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