First slide

Radiation

Question

A solid cube and a solid sphere of the same material have equal surface area. Both are at the same temperature $120^{0} C,$ then

Moderate

A

Both the cube and the sphere cool down at the same rate
B

The cube cools down faster than the sphere
C

The sphere cools down faster than the cube
D

Whichever is having more mass will cool down faster

Solution

Rate of cooling of a body R = $\frac{∆ θ}{t} = \frac{A \in σ (T^{4} - {T_{0}}^{4})}{mc}$
$\Rightarrow R directly proportional to \frac{A}{m} is directly proportional to \frac{Area}{Volume}$
$\Rightarrow$ For the same surface area. R directly proportional to $\frac{1}{Volume}$
Volume of cube < Volume of sphere
$\Rightarrow R_{Cube} > R_{sphere} i . e ., cube, cools down with faster rate$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App