Science (English Medium) Class 11 - CBSE Question Bank Solutions for Physics

Water is flowing in streamline motion through a tube with its axis horizontal. Consider two points A and B in the tube at the same horizontal level.
(a) The pressures at A and B are equal for any shape of the tube.
(b) The pressures are never equal.
(c) The pressures are equal if the tube has a uniform cross section.
(d) The pressures may be equal even if the tube has a nonuniform cross section.

Two wires are kept tight between the same pair of supports. The tensions in the wires are in the ratio 2 : 1 the radii are in the ratio 3 : 1 and the densities are in the ratio 1 : 2. Find the ratio of their fundamental frequencies.

A 2 m long string fixed at both ends is set into vibrations in its first overtone. The wave speed on the string is 200 m s⁻¹ and the amplitude is 0⋅5 cm. (a) Find the wavelength and the frequency. (b) Write the equation giving the displacement of different points as a function of time. Choose the X-axis along the string with the origin at one end and  t = 0 at the instant when the point x = 50 cm has reached its maximum displacement.

When we place a gas cylinder on a van and the van moves, does the kinetic energy of the molecules increase? Does the temperature increase?

Comment on the following statement: the temperature of all the molecules in a sample of a gas is the same.

Consider a gas of neutrons. Do you expect it to behave much better as an ideal gas as compared to hydrogen gas at the same pressure and temperature?

It is said that the assumptions of kinetic theory are good for gases having low densities. Suppose a container is so evacuated that only one molecule is left in it. Which of the assumptions of kinetic theory will not be valid for such a situation? Can we assign a temperature to this gas?

A gas is kept in an enclosure. The pressure of the gas is reduced by pumping out some gas. Will the temperature of the gas decrease by Charles's low?

If the molecules were not allowed to collide among themselves, would you expect more evaporation or less evaporation?

Is it possible to boil water at room temperature, say 30°C? If we touch a flask containing water boiling at this temperature, will it be hot?

Which of the following parameters is the same for molecules of all gases at a given temperature?

The pressure of an ideal gas is written as \[P = \frac{2E}{3V}\] . Here E refers to 

The mean square speed of the molecules of a gas at absolute temperature T is proportional to 

The calorie is defined as 1 cal = 4.186 joule. Why not as 1 cal = 4 J to make the conversions easy?

The process on an ideal gas, shown in figure, is

A calorimeter is kept in a wooden box to insulate it thermally from the surroundings. Why is it necessary?

Which of the following quantities is the same for all ideal gases at the same temperature?
(a) The kinetic energy of 1 mole
(b) The kinetic energy of 1 g
(c) The number of molecules in 1 mole
(d) The number of molecules in 1 g