Physics questions
20027 published questions with worked solutions.
- A body cools room 70°C to 50°C in 6 minutes. If the temperature of surrounding is 30°C, what is the temperature after 12 minutes?
- A body cools from 80°C to 60°C in one minute calculate the time in which the body cools from 60°C to 50°C, if the temperature of...
- The temperature of a solid falls from 77°C to 73°C in 3 minutes and from 73°C to 69°C in 4 minutes what is the temperature of the...
- Newton's law of cooling applies to :
- A body cools from 50.0°C to 49.9°C in 5 second. How long will it take to cool from 40.0°C to 39.9°C? (Assume the temperature of...
- A body cools from 60°C to 50°C in 10 minutes. If room temperature is 25°C and assuming Newton's law of cooling to hold good, the...
- In a room where the temperature is 30°C, a body cools from 61°C to 59°C in 4 minutes. The time taken by the body to cool from...
- Radiant energy from the sun strikes the earth at the rate of 1.4 10^3 watt/m^2. Then the temperature of the surface of the sun is...
- The ratio of energy of emitted radiation of black body at 27°C and 927°C is
- The present value of solar constant 'S' is 1340 W/m^2. If suddenly Earth's orbit around the Sun reduces by half of the present...
- According to Prevost's theory every object
- Two balls A and B are made of same material, but the diameter of B is four times that of A. Both are heated to the same...
- A blackened metal foil is warmed by radiation from a point source, whose temperature is T and distance from the foil is d. It is...
- If wavelengths of max intensity of radiation emitted by sun and moon are 0.5 10^ -6 m and 10^ -4 m resp. The ratio of their temps...
- By what factor should the Kelvin temperature of an object be increased to triple the radiant energy emitted per second by the...
- A body radiates heat at the rate of 50 J/s at 250 K. When the same body is at 750 K, then its rate of radiation of heat will be
- Liquid is filled in vessel which is kept in room having temperature 20°C. When the temperature of the liquid is 80°C, it loses...
- The sun radiates energy in all directions. The average radiations received on the earth's surface from the sun per second is 1.4...
- A piece of metal and a piece of wood are kept at a temperature of 45^ on touching the two with hand: [MP PMT 1993]
- A black body with initial temperature of 300^ is allowed to cool inside an evacuated enclosure surrounded by melting ice at the...