One day in morning, Ramesh filled up frac {1}{3} bucket of hot water from geyser, to tak

English

Gujarati

Hindi

10-2.Transmission of Heat

medium

One day in the morning, Ramesh filled up $\frac {1}{3}$ bucket of hot water from geyser, to take bath. Remaining $\frac {2}{3}$ was to be filled by cold water (at room temperature) to bring mixture to a comfortable temperature. Suddenly Ramesh had to attend to something which would take some times, say $5-10$ $\min$ before he could take bath. Now he had two options: $(1)$ fill the remaining bucket completely by cold water and then attend to the work, $(2)$ first attend tothe work and fill the remaining bucket just before taking bath. Which option do you think would have kept water warmer ? Explain.

Option A

Option B

Option C

Option D

Solution

In first option, water will be hot (warm) and convenient to bath because according to Newton's law of cooling, cooling rate proportion to temperature difference of substance and surrounding is direct and in this first option temperature difference is low hence cooling rate is also low hence water will not become very cool.

Standard 11

Physics

A hollow copper sphere $S$ and a hollow copper cube $ C$ , both of negligible thin walls of same area, are filled with water at $90°C$ and allowed to cool in the same environment. The graph that correctly represents their cooling is

hard

The initial temperature of a body is $80°C$ . If its temperature falls to $64°C$ in $5$ minutes and in $10$ minutes to $52°C$ then the temperature of surrounding will be …… $^oC$

hard

Two friends $A$ and $B$ are waiting for another friend for tea. $A$ took the tea in a cup and mixed the cold milk and then waits. $B$ took the tea in the cup and then mixed the cold milk when the friend comes. Then the tea will be hotter in the cup of

medium

A body takes $5$ minutes to cool from $90^oC$ to $60^oC$. If the temperature of the surroundings is $20^oC$, the time taken by it to cool from $60^oC$ to $30^oC$ will be …… $\min.$

medium

Equal masses of two liquids are filled in two similar calorimeters. The rate of cooling will

easy

Solution

Similar Questions

A hollow copper sphere $S$ and a hollow copper cube $ C$ , both of negligible thin walls of same area, are filled with water at $90°C$ and allowed to cool in the same environment. The graph that correctly represents their cooling is

The initial temperature of a body is $80°C$ . If its temperature falls to $64°C$ in $5$ minutes and in $10$ minutes to $52°C$ then the temperature of surrounding will be …… $^oC$

Two friends $A$ and $B$ are waiting for another friend for tea. $A$ took the tea in a cup and mixed the cold milk and then waits. $B$ took the tea in the cup and then mixed the cold milk when the friend comes. Then the tea will be hotter in the cup of

A body takes $5$ minutes to cool from $90^oC$ to $60^oC$. If the temperature of the surroundings is $20^oC$, the time taken by it to cool from $60^oC$ to $30^oC$ will be …… $\min.$

Equal masses of two liquids are filled in two similar calorimeters. The rate of cooling will

Start a Free Trial Now