Electricity Worksheet-24
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An electric iron draws a current of 1.5 A when the voltage is 200 volts. Calculate the amount of electric charge flowing through it in one hour.
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An electric appliance draws a current of 0.4 A when the voltage is 200 volts. Calculate the amount of charge flowing through it in one hour.
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Calculate the amount of charge that would flow in 1 hour through the element of an electric bulb drawing a current of 0.2 A.
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Calculate the amount of charge that would flow in 2 hours through the element of an electric bulb drawing a current of 0.25 A.
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Calculate the amount of charge that would flow in 1 hour through the element of an electric iron drawing a current of 0.4 A.
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Draw a circuit diagram to show how two resistor are connected in series.
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A bulb is rated at 5.0 V, Calculate its (i) power and (ii) resistance.
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An electric iron has a rating of 750 W, 220 V. Calculate
(i) current passing through it, and (iii) its resistance, when in use.
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An electric lamp is marked 100 W, 220 V. It is used for 5 hours daily. Calculate (i) its resistance while glowing (ii) energy consumed in kWh per day.
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A piece of wire of resistance 20 Ω is drawn out so that its length is increased to twice its original length. Calculate the resistance of the wire in the new situation.
Answer:
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Q = It = 0.5 × 3600 = 1800 C.
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Q = It = 0.4 A × 1 hour = 0.4 A × 3600 s = 1440 C.
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Q = It = 0.2 A × 1 hour = 0.2 A × 3600 s = 720 C.
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Q = It = 0.25 A × 2 × 3600 s = 1800 C.
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Q = I t = 0.4 × 1 hour = 0.4 × 3600 s = 1440 C.
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The circuit diagram is shown in
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V = 5.0 V, I = 100mA = 100 × 10–3 A = 10–1 A,
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Here, p = 750 W, V = 220 V
(i) AS 
(ii) 
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p = 100 W, V = 220 V, t = 5 h
Energy consumed per day is given by
E = p × t = 100 W × 5 h = 500 Wh = 0.5 kWh
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if the original length and the cross – sectional area of the wire are L and A respectively,
When the length becomes 2L and cross – sectional area is A/2, 
From (i) and (ii), 
