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Why is the heating element of an electric oven wound on a helix? State the reason.
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The electric bulbs used these days have a coil-coiled filament. State its reason.
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What changes in energy occur in an electric bulb?
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What changes in energy occur in an electric heater?
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An electric filament lamp is connected to a supply of voltage higher than the recommended value. Give reasons, why compared with a normal performance, the lamp emits a brighter light and its life is shortened.
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‘The current rating of a fuse is 5A’. Comment on this statement.
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Two lamps are rated 220V, 50W and the other rated 220V, 100W are connected in series with the mains of 220 V. Explain, why the 50W lamp glows more?
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Why does not the heating coil produce any visible light? in an electric stove.
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Of the three connecting wires in a household circuit: Which two of the three wires are at the same potential? In which of the three wires should the switch be connected?
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State two advantages of filling an inert gas in an evacuated electric filament lamp.
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A device is used to transform 12 V a.c. to 200 V a.c. What is the name of this device? Name the principle on which it works.
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Which material is the calorimeter commonly made of? Give one reason for using this material.
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Name a metal that is used as an electron emitter. Give one reason for using this metal.
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What is ‘Rating’ of an electric appliance?
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If the rating of an electric bulb is 100W – 230V, Explain its meaning.
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What would happen and why, to an electric bulb when it is connected across a supply of voltage (i) lower (ii) higher than its proper rating?
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An electric bulb is marked 100 W, 230 V. What does this mean?
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Two electric lamps each rating 100 W, 110 V are connected in series to a 220 V power supply and two other electric lamps each of marking 100 W, 220 V are connected in parallel to the same power supply. Will anyone of the two combinations give more light than the other? Give a reason for your answer.
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What is the order of current drawn by appliances connected to the ‘light circuit’ of a household?
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What is the order of current drawn by appliances connected to the ‘power circuit’ of a household?
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