Science (English Medium) कक्षा ११ - CBSE Question Bank Solutions for Physics

Find the ratio of the lengths of an iron rod  and an aluminium rod for which the difference in the lengths is independent of temperature. Coefficients of linear expansion of iron and aluminium are 12 × 10^–6 °C^–1 and 23 × 10^–6 °C^–1 respectively.

An aluminium plate fixed in a horizontal position has a hole of diameter 2.000 cm. A steel sphere of diameter 2.005 cm rests on this hole. All the lengths refer to a temperature of 10 °C. The temperature of the entire system is slowly increased. At what temperature will the ball fall down? Coefficient of linear expansion of aluminium is 23 × 10^–6 °C^–1 and that of steel is 11 × 10^–6 °C^–1.

A glass window is to be fit in an aluminium frame. The temperature on the working day is 40°C and the glass window measures exactly 20 cm × 30 cm. What should be the size of the aluminium frame so that there is no stress on the glass in winter even if the temperature drops to 0°C? Coefficients of linear  expansion for glass  and aluminium are 9.0 × 10^–6 °C^–1 and 24 ×100^–6°C^–1 , respectively.

Does a gas have just two specific heat capacities or more than two? Is the number of specific heat capacities of a gas countable?

Can we define specific heat capacity at constant temperature?

Can we define specific heat capacity for an adiabatic process?

Does a solid also have two kinds of molar heat capacities C_p and C_v? If yes, is C_p > C_v? Or is C_p − C_v = R?

Can a process on an ideal gas be both adiabatic and isothermal?

Show that the slope of the p−V diagram is greater for an adiabatic process compared to an isothermal process.

Can two states of an ideal gas be connected by an isothermal process as well as an adiabatic process?

In a room containing air, heat can go from one place to another

In an isothermal process on an ideal gas, the pressure increases by 0.5%. The volume decreases by about

Two samples A and B are initially kept in the same state. Sample A is expanded through an adiabatic process and the sample B through an isothermal process. The final volumes of the samples are the same. The final pressures in A and B are p_A and p_Brespectively.

Let ∆W_a and ∆W_b be the work done by the systems A and B, respectively, in the previous question.

Consider the processes A and B shown in the figure. It is possible that

Three identical adiabatic containers A, B and C contain helium, neon and oxygen, respectively, at equal pressure. The gases are pushed to half their original volumes.
(a) The final temperatures in the three containers will be the same.
(b) The final pressures in the three containers will be the same.
(c) The pressures of helium and neon will be the same but that of oxygen will be different.
(d) The temperatures of helium and neon will be the same but that of oxygen will be different.

5 g of a gas is contained in a rigid container and is heated from 15°C to 25°C. Specific heat capacity of the gas at constant volume is 0.172 cal g⁻¹ °C⁻¹ and the mechanical equivalent of heat is 4.2 J cal⁻¹. Calculate the change in the internal energy of the gas

A sample of air weighing 1.18 g occupies 1.0 × 10³ cm³ when kept at 300 K and 1.0 × 10⁵ Pa. When 2.0 cal of heat is added to it at constant volume, its temperature increases by 1°C. Calculate the amount of heat needed to increase the temperature of air by 1°C at constant pressure if the mechanical equivalent of heat is  4.2 × 10⁷ erg cal⁻¹. Assume that air behaves as an ideal gas.

An ideal gas expands from 100 cm³ to 200 cm³ at a constant pressure of 2.0 × 10⁵ Pa when 50 J of heat is supplied to it. Calculate (a) the change in internal energy of the gas (b) the number of moles in the gas if the initial temperature is 300 K (c) the molar heat capacity C_p at constant pressure and (d) the molar heat capacity C_v at constant volume.