Complete the following by choosing the correct answers from the bracket: (a) A car is moving in uniform circular motion. The direction of friction between the tyres and the path is ............... [towards the centre / tangential to the path]. (b) When a ray of light passes from a denser to a rarer medium, its wavelength ............... [decreases / increases]. (c) The lid of a calorimeter minimises heat loss by ............... [convection / radiation]. (d) Quality of sound depends on its ............... [amplitude / waveform]. (e) A substance whose resistance becomes almost negligible at a temperature near absolute zero is called a ............... [semiconductor / superconductor]. (f) ............... radiation deviates minimum in a magnetic field [Alpha / Beta].

(a) Atmospheric temperature after a hailstorm is greater than the temperature during the hailstorm. State True or False. (b) Which thermal physical quantity of a frying pan changes by making its base heavier? (c) State the principle of Calorimetry.

Equal masses of substances A, B and C, each at its melting point, take 5 minutes, 7 minutes and 3 minutes respectively to melt when heated at the same rate. Which has the highest specific latent heat of fusion? (a) A (b) B (c) C (d) All are equal

A metal piece of thermal capacity 40 J K−1 absorbs 800 J of heat. Calculate the rise in the temperature of this metal piece.

When the length of a stretched metallic wire is doubled, its specific heat: (a) becomes double (b) becomes four times (c) becomes one-fourth (d) remains the same

Calculate the amount of heat absorbed by 200 g of paraffin wax to melt completely at its melting point. [Specific latent heat of fusion of paraffin wax = 146 J g⁻¹]

Calculate the total amount of heat energy required to melt 200 g of ice at 0°C to water at 100°C. (Specific latent heat of ice = 336 J g−1, specific heat capacity of water = 4.2 J g−1 °C−1)

Specific heat capacity of a substance X is 1900 J kg−1 °C−1 means: (a) Substance X absorbs 1900 J for 1°C rise in temperature (b) 1 kg of substance X absorbs 1900 J heat for 1°C rise in temperature (c) 1 kg of substance X absorbs 1900 J heat to increase the temperature (d) 1 kg of substance X absorbs 1900 J heat to cool down by 1°C

(a) State the principle of calorimetry. (b) Name the material used for making a calorimeter. (c) Write one characteristic property of the material chosen for making a calorimeter.

Thermal capacities of substances A and B are same. If mass of A is more than mass of B then: (a) Which substance will have more specific heat capacity? (b) Which substance will show greater rise in temperature if the same amount of heat is supplied to both?

Specific latent heat of a substance: (a) is directly proportional to the mass (b) is directly proportional to the change in the temperature (c) depends on the material (d) is inversely proportional to the mass

85 g of water at 30°C is cooled to 5°C by adding certain mass of ice. Find the mass of ice required. [Specific heat capacity of water = 4.2 J g−1 °C−1, Specific latent heat of fusion = 336 J g−1]