Assertion The rate of loss of heat of a body at 300 K is R. At 900 K, the rate of loss becomes 81 R. ReasonThis is as per Newton's law of cooling.

Question

Assertion The rate of loss of heat of a body at 300 K is R. At 900 K, the rate of loss becomes 81 R. ReasonThis is as per Newton's law of cooling. (A) Both Assertion and Reason are correct and Reason is the correct explanation of Assertion. (B) Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion. (C) Assertion is correct but Reason is incorrect. (D) Assertion is incorrect but Reason is correct.

Tardigrade Admin · Accepted Answer

Stefan's law is applied here not the Newton's law of cooling.
According to Stefan's law,

\frac{E _{2}}{E _{1}} = (\frac{T _{2}}{T _{1}})^{4} = (\frac{900}{300})^{4} = 81

⟹ \frac{F _{2}}{R} = 81

Therefore,

E_{2} = 81 R

Therefore, Assertion is correct but Reason is incorrect.

Q. Assertion The rate of loss of heat of a body at 300K is R. At 900K, the rate of loss becomes 81R. ReasonThis is as per Newton's law of cooling.

Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.

Assertion is correct but Reason is incorrect.

Assertion is incorrect but Reason is correct.

Stefan's law is applied here not the Newton's law of cooling. According to Stefan's law, E1​E2​​=(T1​T2​​)4=(300900​)4=81 ⟹RF2​​=81 Therefore, E2​=81R Therefore, Assertion is correct but Reason is incorrect.

Q. Assertion The rate of loss of heat of a body at $300 K$ is $R$ . At $900 K$ , the rate of loss becomes $81 R$ .
ReasonThis is as per Newton's law of cooling.

Stefan's law is applied here not the Newton's law of cooling.
According to Stefan's law,
$\frac{E _{2}}{E _{1}} = (\frac{T _{2}}{T _{1}})^{4} = (\frac{900}{300})^{4} = 81$
$⟹ \frac{F _{2}}{R} = 81$
Therefore, $E_{2} = 81 R$
Therefore, Assertion is correct but Reason is incorrect.