JEE Physics Online Test Thermal Properties Of Matter Set E

1. If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q?

2.

3. We consider the radiation emitted by the human body. Which one of the following statements is correct?

4. The Wien‰Ûªs displacement law expresses the relation between

5. A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turns to white hot. The correct explanation for the above observation is possible by using

6.

7. A black body at 1227å¡C emits radiations with maximum intensity at a wavelength of 5000 ÌÉ. If the temperature of the body is increased by 1000å¡C, the maximum intensity will be observed at

8. A beaker full of hot water is kept in a room. If it cools from 80å¡C to 75å¡C in t₁ minutes, from 75å¡C to 70å¡C in t₂ minutes and from 70å¡C to 65å¡C in t₃ minutes, then

9. A black body at 227å¡C radiates heat at the rate of 7 cals/cm²s. At a temperature of 727å¡C, the rate of heat radiated in the same units will be

10. For a black body at temperature 727å¡C, its rate of energy loss is 20 watt and temperature of surrounding is 227å¡C. If temperature of black body is changed to 1227å¡C then its rate of energy loss will be

11. A black body is at 727å¡C. It emits energy at a rate which is proportional to

12. Which of the following is closest to an ideal black body?

13. A black body is at a temperature of 500 K. It emits energy at a rate which is proportional to

14. Gravitational force is required for

15. A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod, when placed in thermal contact with the two reservoirs in time t?

16. Which of the following rods, (given radius r and length l ) each made of the same material and whose ends are maintained at the same temperature will conduct most heat?

17. Consider a compound slab consisting of two pieces of same length and different materials having equal thicknesses and thermal conductivities K and 2 K, respectively. The equivalent thermal conductivity of the slab is

18. Consider two rods of same lengths and different specific heats (S₁, S₂), conductivities (K₁, K₂) and area ofcross-sections (A₁, A₂) and both having temperatures T₁, and T₂ at their ends. If rate of flow of heat due to conduction is equal, then

19. Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K₁ and K₂and cross sectional areas A₁and A₂, respectively. If the rate of heat conductionin 1 is four times that in 2, then

20. A cylindrical rod has temperatures T₁ and T₂ at its ends. The rate of flow of heat is Q (cal/s). If all the linear dimensions are doubled keeping temperatures constant, then rate of flow of heat Q₂ will be

21. Heat is flowing through two cylindrical rods of the same material. The diameters of the rods are in the ratio 1 : 2 and the lengths in the ratio 2 : 1. If the temperature difference between the ends is same, then ratio of the rate of flow of heat through them will be

22. If 1 g of steam at 100å¡C steam is mixed with 1 g of ice at 0å¡C, then resultant temperature of the mixture is

23. When 1 kg of ice at 0å¡C melts to water at 0å¡ C, the resulting change in its entropy, taking latent heat of ice to be 80 cal/å¡C is

24. A slab of stone of area 0.36 m² and thickness 0.1 m is exposed on the lower surface to steam at 100å¡C. A block of ice at 0å¡C rests on the upper surface of the slab. In one hour 4.8 kg of ice is melted. The thermal conductivity of slab is (Given latent heat of fusion of ice = 3.36 ÌÑ 10⁵ J kg^‰ÛÒ1 )

25. Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time?

26. The density of water at 20å¡C is 998 kg/m³ and at 40å¡C 992 kg/m³. The coefficient of volume expansion of water is

27. On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39å¡W and 239å¡W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39å¡C on the Celsius scale?