Two spherical objects (I) and (II) are placed in same surrounding, their emissivity (e) and radius are shown in figure. If in some time interval, $100 J$ of energy is absorbed by the object (I), then amount of energy absorbed) by object (II) in same time interval comes out to be $(100 N) J,$ find $N .$

Important Questions on Thermal Properties of Matter

EASY

JEE Main/Advance

IMPORTANT

Gamma Question Bank for Engineering Physics>Chapter 10 - Thermal Properties of Matter>Assignment>Q 14

A spherical black body of radius

12 cm

at

500 K

is radiating

450 J

of energy per second. If radius of sphere is made half of its initial value and temperature is doubled then power radiated by the body becomes

(600 N) W

find

N .

EASY

JEE Main/Advance

IMPORTANT

Gamma Question Bank for Engineering Physics>Chapter 10 - Thermal Properties of Matter>Assignment>Q 15

Consider a hollow cylinder of inner radius $a$ and outer radius $2 a,$ lateral surface of cylinder is insulated and there is a temperature difference of $Δ T$ between its ends, and $E_{0} = \frac{N π a^{2} k Δ T}{L}$ is the rate of energy flow, then value of $N$ is ( k : Thermal conductivity of material)