The colour of a star tells about its temperature, and the temperature depends on some combination of the star’s mass and evolutionary phase.

Correct Option: A

The colour of a star tells about its temperature, and the temperature depends on some combination of the star’s mass and evolutionary phase.

An Optical Fiber works on the principle of Total Internal Reflection. Light rays are reflected and guided down the length of an optical fiber. The acceptance angle of the fiber determines which light rays will be guided down the fiber.

Correct Option: A

An Optical Fiber works on the principle of Total Internal Reflection. Light rays are reflected and guided down the length of an optical fiber. The acceptance angle of the fiber determines which light rays will be guided down the fiber.

Since Torque = force x distance, to open a door easily, the handle should be fixed at the greatest distance from the hinges. If we pull with same force on a handle that is 2 feet away from the hinges, we will provide twice the torque, so it will be twice as easy to open.

Correct Option: D

Since Torque = force x distance, to open a door easily, the handle should be fixed at the greatest distance from the hinges. If we pull with same force on a handle that is 2 feet away from the hinges, we will provide twice the torque, so it will be twice as easy to open.

Moment of inertia is the mass property of a rigid body that determines the torque needed for a desired angular acceleration about an axis of rotation. Moment of inertia depends on the shape of the body and the amount and distribution of its mass. It can be found through the sum of moments of inertia of the masses making up the whole object, under the same conditions.

Correct Option: B

Moment of inertia is the mass property of a rigid body that determines the torque needed for a desired angular acceleration about an axis of rotation. Moment of inertia depends on the shape of the body and the amount and distribution of its mass. It can be found through the sum of moments of inertia of the masses making up the whole object, under the same conditions.

In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band.

Correct Option: D

In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band.