What is the energy consumed in joules by a bulb that draws 0.5 A across 220V that is on for 10 hours? *
10 points
a. 1100 joules
b. 11 joules
c. 3960 joules
d. 3960000 Joules
Answers
Answer:
option no. a
Explanation:
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Given :
Current passing through bulb, I = 0.5A
Potential difference, V = 220V
Time, t = 10hrs = 36000
To find :
The energy consumed by the bulb
Solution :
Firstly, we have to find resistance of the bulb
using ohm's law .i.e.,
At constant temperature the current flowing through a conductor is directly proportional to the potential difference across its ends.
V = RI
where,
- V denotes potential difference
- R denotes resistance
- I denotes current
substituting all the given values in the formula,
➠ V = RI
➠ 220 = R × 0.5
➠ R = 220/0.5
➠ R = 440Ω
Now, using joules law of heating,
The heat produced in a wire is directly proportional to
- square of current (I²)
- resistance of wire (R)
- time (t) for which current is passed.
In order words,
H = I²Rt
where,
- H denotes Heat produced.
- I denotes current.
- R denotes resistance.
- t denotes time
substituting all the given values in the formula,
➠ H = I² × R × t
➠ H = (0.5)² × (440) × 36000
➠ H = 2.5 × 440 × 36000
➠ H = 3,96,00,000 J
➠ H = 39.6 × 10⁶J
thus, option d is correct answer.