Start Free Mock LoginAlready registered? Login here

Physics - Heat & Thermo Question with Solution | TestHub

PhysicsHeat & ThermoRadiationMedium2 minQB

PhysicsMediumsingle choice

Passage / Comprehension

A metal block remains in a room at 10°C for a long time. It is heated with a 500 W heater until it reaches 50°C. Its initial temperature-rise rate is 2.5°C/s. After the heater is switched off, a 100 W heater is needed to hold it at 50°C. Assume Newton's law of cooling.

What is the rate of cooling of block at 50°C if the 100W heater is also switched off?

Options:

Answer:

Solution:

At 50°C, the 100 W heater balances the heat loss.
$C \frac{d T}{d t} = 100$
$\frac{d T}{d t} = \frac{100}{200} = 0. 5^{\circ} C / s$
Answer B.

Stream:JEESubject:PhysicsTopic:Heat & ThermoSubtopic:Radiation

⏱ 2mℹ️ Source: QB

Doubts & Discussion

Loading discussions...