Advertisements
Advertisements
प्रश्न
On a hot summer day we want to cool our room by opening the refrigerator door and closing all the windows and doors. Will the process work?
Advertisements
उत्तर
No. When the door of the refrigerator is left open in a closed room, the heat given out by the refrigerator to the room will be more than that taken from the room. Therefore, instead of decreasing, the temperature of the room will increase at a slower rate.
APPEARS IN
संबंधित प्रश्न
A body cools from 80 °C to 50 °C in 5 minutes. Calculate the time it takes to cool from 60 °C to 30 °C. The temperature of the surroundings is 20 °C.
On a cold winter night you are asked to sit on a chair. Would you like to choose a metal chair or a wooden chair? Both are kept in the same lawn and are at the same temperature.
The temperature of the atmosphere at a high altitude is around 500°C. Yet an animal there would freeze to death and not boil. Explain.
Newton's law of cooling is a special case of
Newton's law of cooling leads to the expression:
Two circular discs A and B with equal radii are blackened. They are heated to the same temperature and are cooled under identical conditions. What inference do you draw from their cooling curves?
A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is correct?
- The rate of cooling is constant till milk attains the temperature of the surrounding.
- The temperature of milk falls off exponentially with time.
- While cooling, there is a flow of heat from milk to the surrounding as well as from surrounding to the milk but the net flow of heat is from milk to the surounding and that is why it cools.
- All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings.
Is the bulb of a thermometer made of diathermic or adiabatic wall?
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 attend 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 kept water warmer? Explain.
What is the shape of the cooling curve T vs t?
Why must the surrounding temperature T₀ remain constant in the experiment?
A metal sphere cools in a room at 30°C. At T = 70°C, dT/dt = −1.6°C/min. Find C.
A body is cooling from 80°C to 60°C in a room at 30°C. Compared to the time taken to cool from 60°C to 40°C, the time taken to cool from 80°C to 60°C will be ______.
The cooling curve of a hot body is a graph of temperature T versus time t. What is the correct description of this curve?
