Why does the glow on bulb increases with the increase in resistance of the filament of the bulb with the increase in temperature (when resistance is inversely proportional to conductance)?

Asked by nidhisingh200418 | 24th Jul, 2019, 12:44: AM

Expert Answer:

Power dissipation i2R is directly proportional to square of current and directly proportional to Resistance.
As the resistance of filament increases due to increase in temperature, current variation will be negligible because of 240V potential difference.
Hence power dissipation increases in filament due to increase in temperature and that makes again temperature to increase.
When temperature of hot body increases, intensity of visible part of thermal radiation increases.
Hence glow of bulb increases with increase in resistance of filament , while resistance increases with increase of temperature

Answered by Thiyagarajan K | 24th Jul, 2019, 08:19: AM

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