Explanation

Dry ice is a solid form of carbon dioxide.

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"Dry ice" is solid, frozen carbon dioxide, which is sublimated at a chilly -78.5 °C (-109.3°F).

Dry ice is used primarily as a cooling agent.

Dry ice does not melt into a liquid when heated instead, it changes directly into a gas.

ND16-8-2023

Explanation

The hardest substance in the world is diamond.

Its hardness is due to the strong covalent bonding between its carbon atoms.

This making it the most resistant to scratching.

Category: Native minerals

Cleavage: 111 (perfect in four directions)

Crystal class: Hexoctahedral (m3m); H-M symbol: (4/m 3 2/m)

Crystal habit: Octahedral

Crystal system: Cubic

Dana classification: 1.3.6.1

Density: 3.5–3.53 g/cm3 3500–3530 kg/m3

Explanation

Hypertension (high blood pressure) is a non-viral disease.

Whereas HIV/Aids, Measles, and Influenza are all viral diseases.

Explanation

• Atoms of the same element with different numbers of neutrons are called isotopes.
• Atoms of the same element have the same number of protons and electrons but different numbers of neutrons.

Explanation

Lead is commonly used as a shield against gamma rays.

Due to its high density.

It effectively absorbs and blocks gamma radiation.

Explanation

Albert Einstein, a renowned physicist, revolutionized physics with his theory of relativity.

He made significant contributions to mathematics and philosophy as well.

Einstein is celebrated as one of the most influential physicists of the 20th century.

It notably publishing four landmark papers in 1905.

Explanation

A convex lens has either one or both of its surfaces curving outwards, that is, wider divergence from the plan at the center.

These lenses are used to correct long-sightedness (hypermetropia).

Explanation

Formic acid is present in the sting of ants.

It causes a sharp, burning sensation and irritation when injected into the skin during an ant sting.

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.