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

In the given progressive wave y = 5 sin (100 πt – 0.4 πx) where y and x are in m, t is in s. What is the frequency.

In the given progressive wave y = 5 sin (100 πt – 0.4 πx) where y and x are in m, t is in s. What is the wave velocity.

In the given progressive wave y = 5 sin (100 πt – 0.4 πx) where y and x are in m, t is in s. What is the particle velocity amplitude.. 

Given a + b + c + d = 0, state whether the following statement is correct or incorrect:

b + c must lie in the plane of a and d if a and d are not collinear, and in the line of a and d, if they are collinear.

Establish the following vector inequalities geometrically or otherwise:

1. | a+b | ≤ |a| + |b|
2. |a + b| ≥ | |a| - |b| |
3. |a - b| ≤ |a| + |b|
4. |a-b| ≥ | |a| - |b| |

When does the equality sign above apply?

Two heavy spheres each of mass 100 kg and radius 0.10 m are placed 1.0 m apart on a horizontal table. What is the gravitational force and potential at the mid point of the line joining the centers of the spheres? Is an object placed at that point in equilibrium? If so, is the equilibrium stable or unstable?

A star 2.5 times the mass of the sun and collapsed to a size of 12 km rotates with a speed of 1.2 rev. per second. (Extremely compact stars of this kind are known as neutron stars. Certain stellar objects called pulsars belong to this category). Will an object placed on its equator remain stuck to its surface due to gravity? (mass of the sun = 2 x 10³⁰ kg).

Give the magnitude and direction of the net force acting on a drop of rain falling down with a constant speed.

The driver of a three-wheeler moving with a speed of 36 km/h sees a child standing in the middle of the road and brings his vehicle to rest in 4.0 s just in time to save the child. What is the average retarding force on the vehicle? The mass of the three-wheeler is 400 kg and the mass of the driver is 65 kg.

If the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks?

Read each statement below carefully, and state, with reasons, if it is true or false;

 During rolling, the force of friction acts in the same direction as the direction of motion of the CM of the body

Read each statement below carefully, and state, with reasons, if it is true or false;

The instantaneous acceleration of the point of contact during rolling is zero.

A piece of copper having a rectangular cross-section of 15.2 mm × 19.1 mm is pulled in tension with 44,500 N force, producing only elastic deformation. Calculate the resulting strain?

A vertical off-shore structure is built to withstand a maximum stress of 10⁹ Pa. Is the structure suitable for putting up on top of an oil well in the ocean? Take the depth of the ocean to be roughly 3 km, and ignore ocean currents.

What is the pressure inside the drop of mercury of radius 3.00 mm at room temperature? The surface tension of mercury at that temperature (20°C) is 4.65 × 10^–1 N m^–1. The atmospheric pressure is 1.01 × 10⁵ Pa. Also give the excess pressure inside the drop

A tank with a square base of area 1.0 m² is divided by a vertical partition in the middle. The bottom of the partition has a small-hinged door of area 20 cm². The tank is filled with water in one compartment, and an acid (of relative density 1.7) in the other, both to a height of 4.0 m. compute the force necessary to keep the door close.

It is known that density ρ of air decreases with height y as `0^(e^(y/y_0))` Where`rho_0` = 1.25 kg m^–3 is the density at sea level, and y₀ is a constant. This density variation is called the law of atmospheres. Obtain this law assuming that the temperature of atmosphere remains a constant (isothermal conditions). Also, assume that the value of gremains constant

Explain why Two bodies at different temperatures T₁ and T₂, if brought in thermal contact, do not necessarily settle to the mean temperature (T₁ + T₂)/2.

Explain why Air pressure in a car tyre increases during driving.

In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case? (Take 1 cal = 4.19 J)