30 g of ice at 0°C is used to bring down the temperature of a certain mass of water at 70°C to 20°C. Find the mass of water. Specific heat capacity of water = 4.2 J g⁻¹ °C⁻¹ and specific latent heat of ice = 336 J g⁻¹.

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]

Complete the following by choosing the correct answers from the bracket: (a) In uniform circular motion the centrifugal force acts ............... [towards the centre/away from the centre/along the tangential direction]. (b) Refractive index of a medium is independent of ............... [temperature/angle of incidence/wavelength of light]. (c) Heat absorbed during change of phase depends on ............... [mass/change in temperature/specific heat capacity] of the substance. (d) Emf of a cell is ............... [greater than/less than/equal to] the terminal voltage when the cell is in open circuit. (e) In a step-up transformer the turns ratio is ............... [more than 1/less than 1/equal to 1]. (f) The nuclear radiation with lowest ionising power is ............... [α/β/γ].

Each of the substances given below is supplied with same amount of heat. Which one will attain the highest temperature? Substance Specific heat capacity (cal/g°C) Lead 0.031 Aluminium 0.21 Copper 0.095 Iron 0.115 (a) Aluminium (b) Copper (c) Iron (d) Lead

A metal piece of mass 5 g has thermal capacity 2.5 J K⁻¹. If the mass of the metal is tripled, then its specific heat capacity will be : (a) 7.5 J K⁻¹ (b) 2.5 J K⁻¹ (c) 1.5 J g⁻¹ K⁻¹ (d) 0.5 J g⁻¹ K⁻¹

(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.

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)

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]

(a) Why does it become pleasantly warm when the lakes start freezing? (b) Water freezes to form ice. What change would you expect in the average kinetic energy of the molecules? (c) Which will contain more heat energy 1 g of ice at 0°C or 1 g water at 0°C?

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 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

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