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प्रश्न
In an electric radiator or room heater, state with reason, why the porcelain tube wound with a nichrome wire is placed between the pole and principal focus of the parabolic concave reflector.
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उत्तर
In this position, when current passes through the nichrome wire, it becomes red hot and the concave reflector helps in spreading the heat radiation in the room because it forms a divergent beam on account of the heating element being placed between the pole and the principal focus of the reflector.
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