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

Water is filled in a rectangular tank of size 3 m × 2 m × 1 m. (a) Find the total force exerted by the water on the bottom surface on the tank. (b) Consider a vertical side of area 2 m × 1 m. Take a horizontal strip of width δx metre in this side, situated at a depth of x metre from the surface of water. Find the force by the water on this strip. (c) Find the torque of the force calculate in part (b) about the bottom edge of this side.
(d) Find the total force by the water on this side.
(e) Find the total torque by the water on the side about the bottom edge. Neglect the atmospheric pressure and take g = 10 ms⁻². 

Water leaks out from an open tank through a hole of area 2 mm² in the bottom. Suppose water is filled up to a height of 80 cm and the area of cross section of the tanks is 0.4 m². The pressure at the open surface and at the hole are equal to the atmospheric pressure. Neglect the small velocity of the water near the open surface in the tank. (a) Find the initial speed of water coming out of the hole. (b) Find the speed of water coming out when half of water has leaked out. (c) Find the volume of eater leaked out using a time interval dt after the height remained is h. Thus find the decrease in height dh in terms of h and dt.
(d) From the result of park (c) find the time required for half of the water to leak out.

If two bodies are in thermal equilibrium in one frame, will they be in thermal equilibrium in all frames?

If mercury and glass had equal coefficients of volume expansion, could we make a mercury thermometer in a glass tube?

If an automobile engine is overheated, it is cooled by pouring water on it. It is advised that the water should be poured slowly with the engine running. Explain the reason.

Is it possible for two bodies to be in thermal equilibrium if they are not in contact?

A system X is neither in thermal equilibrium with Y nor with Z. The systems Y and Z

For a constant-volume gas thermometer, one should fill the gas at

A gas thermometer measures the temperature from the variation of pressure of a sample of gas. If the pressure measured at the melting point of lead is 2.20 times the pressure measured at the triple point of water, find the melting point of lead.

The density of water at 0°C is 0.998 g cm^–3 and at 4°C is 1.000 g cm^–1. Calculate the average coefficient of volume expansion of water in the temperature range of 0 to 4°C.

A steel rod is clamped at its two ends and rests on a fixed horizontal base. The rod is unstrained at 20°C.
Find the longitudinal strain developed in the rod if the temperature rises to 50°C. Coefficient of linear expansion of steel = 1.2 × 10^–5 °C^–1.

Show that the moment of inertia of a solid body of any shape changes with temperature as I = I₀ (1 + 2αθ), where I₀ is the moment of inertia at 0°C and α is the coefficient of linear expansion of the solid.

A gas kept in a container of finite conductivity is suddenly compressed. The process
(a) must be very nearly adiabatic
(b) must be very nearly isothermal
(c) may be very nearly adiabatic
(d) may be very nearly isothermal

Pure water vapour is trapped in a vessel of volume 10 cm³. The relative humidity is 40%. The vapour is compressed slowly and isothermally. Find the volume of the vapour at which it will start condensing.

Answer the following question.

If `vec"v"_1 = 3hat"i" + 4hat"j" + hat"k" and vec"v"_2 = hat"i" - hat"j" - hat"k"`, determine the magnitude of `vec"v"_1 + vec"v"_2`.

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = –2 sin (3t + π/3)

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = cos `(π/6 - "t")`

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = 3 sin `(2πt + π/4)`