Explanation

Water absorbs red light strongly, so it doesn’t penetrate much.

The scattered shorter wavelengths (like green/blue) dominate, making it appear green.

Explanation

Sound travels fastest in solids because particles are closely packed, allowing quicker vibration transfer.

Velocity of sound: Metal > Water > Air > Vacuum (no sound in vacuum).

Explanation

Electrostatic potential is a scalar quantity because it has magnitude only, no direction.

In contrast, magnetic moment, electric field, and acceleration due to gravity are vector quantities.

Explanation

The SI unit of heat is the joule (J).

Heat is a form of energy.

The joule is the standard unit for energy in the International System of Units (SI).

For instance, 1 joule of heat is the energy required to raise the temperature of 1 gram of water by 0.24°C. 

Explanation

Mustard gas (sulfur mustard) is a viscous liquid at room temperature with a relatively high boiling point.

It was used as a chemical warfare agent because it evaporates slowly, making it effective over time.

Explanation

Noble gases have complete outer electron shells, making them chemically stable.

Because of this stable configuration, they generally show valency = 0.

Explanation

Pure water has extremely low ionization, producing very few H^+ and OH^- ions.

Since electrical conductivity requires free ions, pure water is almost a non-conductor.

Explanation

The reaction at the anode is called oxidation.

In electrochemical cells, the anode is where oxidation occurs, meaning the substance loses electrons.

This contrasts with the cathode, where reduction (gain of electrons) takes place.

Explanation

Sodium (Na) always shows valency = 1, as it loses one electron to form Na⁺.

Iron (Fe) and Hydrogen (H) show variable valencies, while sodium’s valency remains unchanged.

Explanation

∫³-1 dx = [x]³-1 = 3 - (-1) = 4