Explanation

A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a non-SI unit of energy

equal to 3.6 megajoules (MJ) in SI units

.Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities.

Explanation

The ball shares the train’s horizontal velocity, so it moves forward with the train.

As a result, it comes back down into the thrower’s hand.

Explanation

Force is not a base quantity; it is calculated using base quantities (mass and acceleration).

It is a derived quantity because its SI unit (Newton) comes from kg·m/s².

Explanation

Newton's rings are circular fringes formed due to the interference of light reflected from two surfaces.

They appear when a plano-convex lens is placed on a flat glass surface.

Explanation

The Pyrometer is used for measuring very high temperatures.

Pyrometers can measure temperatures without direct contact.

This making them ideal for extreme conditions.

Explanation

Explanation

Explanation

According to Coulomb's Law, the force between two charges is inversely proportional to the square of the distance between them.

If the distance is halved, the force becomes four times stronger.

Explanation

Electric field intensity (E) is defined as force per unit charge: E = F/q.

So its unit is Newton/Coulomb (N/C).

Explanation

Electric flux through a surface is defined clearly only for a closed surface.

Gauss’s Law applies to closed surfaces to calculate total flux.