Embibe Experts Solutions for Chapter: Heat Transfer, Exercise 1: Exercise 1

A black body at high temperature emits radiations of

Let there be four identical cubes having colours blue, red, black and white. When they are heated together and allowed to cool under identical conditions, which cube will cool at the earliest?

A black body at $1227°\mathrm{C}$ emits radiations with maximum intensity at a wavelength of $5000\AA .$ If the temperature of the body is increased by $1000°\mathrm{C},$ the maximum intensity will be at

A liquid cools from $70°\mathrm{C}$ to $50°\mathrm{C}$ in $5$ minutes. Find the time taken by the liquid to cool from $60°\mathrm{C}$ to $50°\mathrm{C}$, if the temperature of the surrounding is constant at $30°\mathrm{C}$.

A body cools from $70°\mathrm{C}$ to $40°\mathrm{C}$ in $5 \min .$ Calculate the time it takes to cool from $60°\mathrm{C}$ to $40°\mathrm{C}.$ The temperature of the surrounding is $20°\mathrm{C}.$

A cube, a cylinder (of height equal to its diameter) and a sphere, all solid, are made of metal and are of identical mass. If all the three shapes having initial temperature $50 °\mathrm{C}$ are put in a large reservoir of water at $10 °\mathrm{C}.$ Which of the above three shapes cools the fastest?

A bucketful of water is kept in a room and it cools from ${75}^{\circ }\mathrm{C}$ to ${70}^{\circ }\mathrm{C}$ in ${\mathrm{T}}_1 \min$, from ${70}^{\circ }\mathrm{C}$ to ${65}^{\circ }\mathrm{C}$ in ${\mathrm{T}}_2 \min$, and from ${65}^{\circ }\mathrm{C}$ to ${60}^{\circ }\mathrm{C}$ in ${\mathrm{T}}_3 \min$. Then