One day in the morning , Ramesh filled up 1/3 bucket of hot water from geyser, to take bath. Remaining 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 minutes before he could take bath. Now he had two options:
(i) Fill the remaining bucket completely by cold water and then attained to the work,
(ii) First attend to the work and fill the remaining bucket just before taking bath. Which option do you think would have water warmer? Explain.
(i) Fill the remaining bucket completely by cold water and then attained to the work,
(ii) First attend to the work and fill the remaining bucket just before taking bath. Which option do you think would have water warmer? Explain.
According to the Newton’s law o‘f cooling, the rate of
loss of heat is directly proportional to the difference of temperature. Or we
can say which gives a consequence about rate of fall of temperature of a body
with respect to the difference of temperature of body and surroundings.
The first option would have kept water warmer because
by adding hot water to cold water, the temperature of the mixture decreases.
Due to this temperature difference between the mixed water in the bucket and
the surrounding decreases, thereby the decrease in the rate of loss of the heat
by the water.
In second option, the hot water in the bucket will
lose heat quickly. So if he first attend to the work and fill the remaining
bucket with cold water which already lose much heat in 5-10 minutes then the
water become more colder as comparison with first case.
According to the Newton’s law o‘f cooling, the rate of loss of heat is directly proportional to the difference of temperature. Or we can say which gives a consequence about rate of fall of temperature of a body with respect to the difference of temperature of body and surroundings.
The first option would have kept water warmer because by adding hot water to cold water, the temperature of the mixture decreases. Due to this temperature difference between the mixed water in the bucket and the surrounding decreases, thereby the decrease in the rate of loss of the heat by the water.
In second option, the hot water in the bucket will lose heat quickly. So if he first attend to the work and fill the remaining bucket with cold water which already lose much heat in 5-10 minutes then the water become more colder as comparison with first case.
