Assuming newton's law of cooling to be valid, body at temperature 50^o C in surrounding of tempe

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10-2.Transmission of Heat

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Assuming newton's law of cooling to be valid, body at temperature $50^o\ C$ in surrounding of temperature $20^o\ C$ , achieve steady state with help of $100\ W$ heater. If same body has temperature $35^o\ C$ in same surrounding, then power of heater required to maintain steady state ........ $W$

A

$70$

B

$50$

C

$100$

D

$35$

Solution

Temperature of surrounding is $20^{\circ} \mathrm{C}$

$50^{\circ} \mathrm{C}$

Heater $100 \mathrm{W}$

$100=\mathrm{K}(50-20)$

$100=\mathrm{K} \times 30$

$35^{\circ} \mathrm{C}$

Heater $XW$

$\mathrm{x}=\mathrm{K}(35-20)$

$\mathrm{x}=\frac{100}{30} \times 15$

$\mathrm{x}=50$

Standard 11

Physics

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