Explanation

Sir Isaac Newton was an English mathematician, physicist, astronomer, alchemist, theologian,

Author widely recognised as one of the greatest mathematicians

And physicists of all time and among the most influential scientists. 

Explanation

The power of the lens is the reciprocal of focal length.

The SI unit is dioptre.

Dioptre (D)

Power of lens = 1/ focal length in meter.

Explanation

A light year is the distance light travels in one year — about 9.46 trillion kilometers.

It is commonly used to measure vast distances between stars and galaxies.

Astronomers use an effect called parallax to measure distances to nearby stars.

Parallax is the apparent displacement of an object because of a change in the observer's point of view.

Explanation

The average distance from the Earth to the Sun is approximately 150 million kilometers.

It is also called 1 astronomical unit (or AU).

Explanation

The rear view mirror used in vehicles is a convex mirror.

It provides a wider field of view and reduces the size of the images.

This making it easier for drivers to see a larger area behind them.

Explanation

Troposphere is the lowest layer of the atmosphere where all weather phenomena occur and where we live.

Exosphere is the outermost layer, gradually merging into space, containing very thin air and satellites.

Explanation

Explanation

Thomas Alva Edison was an American inventor.

He developed many devices: 

• Electric power generation 
•  Mass communication
•  Sound recording
• Motion pictures.

Explanation

Antoine Henri Becquerel was an engineer, physicist, Nobel laureate,

First person to discover evidence of radioactivity.

 He belonged to France.

Explanation

Direct current is produced when electrons flow constantly in one direction.

It's abbreviated as "DC".

Since direct current flows in one direction only, its electrical pressure or voltage is always oriented in one direction, or "polarity".