JEE Advanced Physics Syllabus can be referred by the IIT aspirants to get a detailed list of all topics that are important in cracking the entrance examination. JEE Advanced syllabus for Physics has been designed in such a way that it offers very practical and application-based learning to further make it easier for students to understand every concept or topic by correlating it with day-to-day experiences. In comparison to the other two subjects, the syllabus of JEE Advanced for physics is developed in such a way so as to test the deep understanding and application of concepts.

**62. A pendulum clock having copper rod keeps correct time at 20℃. It gains 15 s per day if cooled to 0°C. The coefficient of linear expansion of copper is**

**Q63. A beaker contains 200 g of water. The heat capacity of the beaker is equal to that of 20 g of water. The initial temperature of water in the beaker is 20°C. If 440 g of hot water at 92°C is poured in it, the final temperature (neglecting radiation loss) will be nearest to**

**Q64. The earth receives on its surface radiation from the sun at the rate of 1400 W/m**

^{2}. The distance of the centre of the sun from the surface of the earth is 1.5×10^{11}m and the radius of the sun is 7.0×10^{8}m. Treating sun as a black body, it follows from the above data that its surface temperature is**Q65. A solid copper sphere (density ρ and specific heat capacity c) of radius r at an initial temperature 200K is suspended inside a chamber whose walls are at almost 0K. The time required (in μ s) for the temperature of the sphere to drop to 100 K is**

**Q66. The design of a physical instrument requires that there be a constant difference in length of 10 cm between an iron rod and a copper cylinder laid side by side at all temperatures. If α_Fe=11×10**

^{(-6)}/℃ and α_cu=17×10^{(-6)}/°C, their length may be**Q68. The coefficient of linear expansion for a certain metal varies with temperature as α(T). If L_0 is the initial length of the metal and the temperature of metal is changed from T_0 to (T_0>T), then**

Solution

**Q69. 5 g of water at 30° C and 5 g of ice at -20°C are mixed together in a calorimeter. Find the final temperature of the mixture. Assume water equivalent of calorimeter to be negligible, sp. heats of ice and water are 0.5 and 1 cal/g C°, and latent heat of ice is 80 cal/g**