Explanation

Helium  and Argon is a noble gas, part of Group 18 in the periodic table.

Helium (He)

The lightest noble gas, helium is used in hot air balloons and airships.

It's also used in air containers for deep-sea divers.

Argon (Ar)

Argon makes up 0.93% of the Earth's atmosphere.

It can be prepared by fractional distillation of liquid air.

Explanation

Sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) are primary precursors of acid rain.

Acid rain is a consequence of these atmospheric pollutants reacting with water, oxygen, and other chemicals to form acidic compounds. 

These acids contribute to environmental damage.

Explanation

The coulomb, also written as its abbreviation 'C', is the SI unit for electric charge.

One coulomb is equal to the amount of charge from a current of one ampere flowing for one second.

One coulomb is equal to the charge on 6.241 x 1018 protons.

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Explanation

The stratospheric ozone layer is Earth's “sunscreen”  protecting living things from too much ultraviolet radiation from the sun.

Oxygen layer in the atmosphere

Ozone protects us from the harmful ultraviolet radiation of the sun.

Ozone formula: O3

The ozone layer lies approximately 15-40 kilometers (10-25 miles) above the Earth's surface, in the stratosphere.

The ozone layer is depleting: Air pollution

ND17-7-2023

Explanation

The energy stored in coal is classified as chemical energy.

It is released during combustion when the chemical bonds in the coal are broken.

This energy is harnessed for heating and electricity generation.

Explanation

• A cataract is a clouding of the lens in the eye that affects vision.
• It is a common age-related condition that can cause blurry vision, double vision, and sensitivity to light.
• Cataracts can be treated with surgery to remove the cloudy lens and replace it with an artificial lens.

Explanation

• ECG (Electrocardiogram) is a test used to measure the electrical activity of the heart.

It is commonly used for the diagnosis of heart-related ailments, such as:

• Arrhythmias (irregular heart rhythms)
• Coronary artery disease
• Cardiac arrests
• Heart failure

Explanation

Explanation

Explanation

Tides are primarily caused by the gravitational pull of both the Moon and the Sun.

The Moon has a stronger effect due to its proximity to Earth.

The Sun's gravitational influence also plays a significant role in the tidal patterns we observe.