Physics Class 12 NCERT Solutions: Chapter 3 Current Electricity Part 3

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Formula of resistance

Formula of Resistance

Q: 8. A heating element using nichrome connected to a supply draws an initial current of which settles after a few seconds toa steady value of . What is the steady temperature of the heating element if the room temperature is ? Temperature coefficient of resistance of nichrome averaged over the temperature range involved is .

Answer:

Supply voltage,

Initial current drawn

Initial resistance, which is given by the relation,

Steady state value of the current,

Resistance at the steady state which is given as

Temperature co-efficient of nichrome,

Initial temperature of nichrome,

Study state temperature reached by nichrome

Can be obtained by the relation for

Therefore, the steady temperature of the heating element is

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