Physics
An electric bulb is rated '250 W, 230 V'. Calculate
(i) the energy consumed in one hour, and
(ii) the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains?
Answer
(i) Given,
Power (P) = 250 W
Voltage (V) = 230 V
Time (t) = 1 h = 3600 sec
Energy (E) = ?
From relation,
E = P × t
Substituting the values in the formula above, we get,
E = 250 x 3600 = 9 x 105 J
Hence, energy consumed in one hour = 9 x 105 J
(ii) Let t be the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains
P = 1.0 kWh = 1000 Wh
Substituting the value in the formula, we get,
1000 = 250 x t
⇒ t = 1000 / 250 = 4 h
Hence, time = 4 h
Related Questions
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A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 ohm. A steady current of 0.5 A flows through the circuit. Calculate —
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