HARD
JEE Main/Advance
IMPORTANT
Earn 100

A lagged stick of cross-section area 1 cm2 length are 1 cm2 and length 1 m is initially at a temperature of 0°C. It is then kept between 2 resevoirs of temperature 100°C and 0°C. Specific heat capacity is 10 J kg°C and linear mass density is 2 kg m-1.

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(i) If temperature gradient along the rod in steady state is -50 n °C m-1 then find the value of n

(ii) If total heat absorbed by the rod to reach steady state is 250 n J then find the value of n.

Important Questions on Heat Transfer

EASY
JEE Main/Advance
IMPORTANT

Calculate the temperature of the black body from given graph.

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HARD
JEE Main/Advance
IMPORTANT
A cylindrical block of length 0.4 m and area of cross-section 0.04 m2 is placed coaxially on a thin metal disc of mass 0.4 kg and of the same cross-section. The upper face of the cylinder is maintained at a constant temperature of 400 K and the initial temperature of the disc is 300 K. If the thermal conductivity of the material of the cylinder is 10 W m-1 K-1 and the specific heat of the material of the disc is 600 J kg-1 K-1, how long will it take for the temperature of the disc to increase to 350 K? Assume for the purpose of calculation, the thermal conductivity of the disc to be very high and the system to be thermally insulated except for the upper face of the cylinder.
HARD
JEE Main/Advance
IMPORTANT
A double-pane window used for insulating a room thermally from outside consists of two glass sheets each of area 1 m2 and thickness  0.01 m separated by a 0.05 m thick stagnant air space. In the steady state, the room glass interface and the glass-outdoor interface are at constant temperature of 27C and 0C respectively. Calculate the rate of heat flow through the window pane. Also find the temperatures of other interfaces. Given thermal conductivities of glass and air as 0.8 and 0.08 W m-1 K-1 respectively.