A partition wall has two layers of different
materials A and B in contact with each other.
They have the same thickness but the thermal conductivity of layer A is twice that of layer B. At steady state if the temperature difference across the layer B is 50 K, then the corresponding difference across the layer A is

• 50 K

• 12.5 K

• 16.6 K

• 60 K

Hot water cools from 60°C to 50°C in the first 10 min and to 42°C in the next 10 min. The temperature of the surroundings is

• 10°C

• 5°C

• 15°C

• 20°C

A bubble of 8 mole of helium is submerged at a certain depth in water. The temperature of water increases by 30°C. How much heat is added approximately to helium during expansion ?

• 4000 J

• 3000 J

• 3500 J

• 4500 J

The plots of intensity of radiation versus wavelength of three black bodies at temperatures T₁, T₂ and T₃ are shown. Then,

• T₃ > T₂ > T₁

• T₁ > T₂ > T₃

• T₂ > T₃ > T₁

• T₁ > T₃ > T₂

Three rods made of same material and having same cross-section are joined as shown in the figure. Each rod is of same length. The temperature at the junction of the three rods is

• 45°C

• 90°C

• 60°C

• 20°C

36.

On heating, the temperature at which water has minimum volume is

• 0° C

• 4° C

• 4 K

• 100° C

The readings of a constant volume gas thermometer at 0°C and 100°C are 40 cm of mercury and 60 cm of mercury. If its reading at an unknown temperature is 100 cm of mercury column, then the temperature is 

• 100°C

• 50°C

• 25°C

• 300°C

A 2 kg copper block is heated to 500°C and then it is placed on a large block of ice at 0°C. If the specific heat capacity of copper is 400 J kg^-1°C^-1 and latent heat of fusion of water is 3.5 x 10⁵ J kg^-1 the amount of ice that can melt is

• 7/8 kg

• 7/5 kg

• 8/7 kg

• 5/7 kg

The volume of a metal sphere increases by 0.24 % when its temperature is raised by 40°C. The coefficient of linear expansion of the metal is 

• 2 × 10^-5

• 6 × 10^-5

• 18 × 10^-5

• 1.2 × 10^-5

The temperature of equal masses of three different liquids A, B and C are 12°C, 19°C and 28°C respectively. The temperature when A and B are mixed is 16°C and when B and C are mixed is 23°C. The temperature when A and C are mixed is

• 18.2°C

• 22°C

• 20.2°C

• 24.2°C