Explanation

Ernest Rutherford showed (1919) that nitrogen under alpha-particle bombardment ejects what appear to be hydrogen nuclei.

By 1920 Ernest Rutherford had accepted the hydrogen nucleus as an elementary particle, naming it proton.

while

Electron was discovered by J. J. Thomson in 1897.

Explanation

Potential energy is the energy an object has due to its position or state.

For example, being elevated in a gravitational field.

It can potentially do work if it moves.

Explanation

Altimeters:

Function:

It primarily measures altitude by detecting changes in atmospheric pressure. 

Aviation use:

Pilots heavily rely on altimeters to determine their aircraft's height above sea level during flight. 

Types:

There are different types of altimeters including pressure altimeters and radio altimeters. 

Explanation

Graphite is a crystalline form of the element carbon.

It consists of stacked layers of graphene.

Graphite occurs naturally and is the most stable form of carbon under standard conditions.

Explanation

Mercury (Hg) is used in thermometers.

Because it expands and contracts consistently with temperature changes.

It providing accurate readings.

It also emits ultraviolet light in fluorescent tubes when electrically excited.

Explanation

Ozone (O₃) is a triatomic (three-atom) allotropic form of oxygen

Allotropy: is when an element exists in different forms in the same physical state. 

Oxygen: is the element in question. 

Ozone (O₃): is the specific allotropic form that contains three oxygen atoms in each molecule. 

Diatomic oxygen (O₂): is the other common allotrope of oxygen, containing two oxygen atoms per molecule. 

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 lifespan of a red blood cell is around 120 days.

Blood cells are made in the bone marrow.

Explanation

Radon is a gas that can be accumulated in poorly ventilated buildings.

Explanation

Biogas produced as a result of anaerobic decay of organic matter consists primarily of methane (CH4) and carbon dioxide (CO2).

Biogas can also contain small amounts of other gases, such as:

• Water vapor
• Hydrogen sulfide (H2S
• Siloxanes