Questions

A Slip ring is a ring in a dynamo or electric motor which is attached to and rotates with the shaft, passing an electric current to a circuit via a fixed brush pressing against it.

Slip rings are usually made of Phosphor Bronze.

Slip ring motors usually have a 'phase-wound' rotor. This type of rotor has a 3-phase, double-layer, distributed winding consisting of coils used in alternators. The rotor core is made up of steel laminations which have slots to accommodate formed 3-single phase windings.

The ball with which Table Tennis is played is called Ping Pong Ball.

According to the International rules, the diameter of the ping pong ball must be not less than 39.5 millimeters and not greater than 40.5  millimeters having a mass of 2.7 grams.

The ozone layer is a region of Earth's Stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere.

The Atmosphere is divided into 4 layers according to major changes in temperature. They are :

1. Troposphere,

2. Stratosphere,

3. Mesosphere  and

4. Thermosphere.

The farther away from earth, the thinner the atmosphere gets.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.

Compressions and Rarefactions are characteristic of Longitudinal waves.

The direction of vibration of the particles is in the same plane as in which the wave is propagating. The particles vibrate back and forth, about their mean positions.