Explanation

• If an object absorbs all seven colors of light (i.e., all the wavelengths of visible light), it appears black.
• This is because no light is being reflected, and our eyes perceive the absence of light as black.
• When an object reflects all the component colors of light, it appears white.

Explanation

• A chemical formula tells us the number of atoms of each element in a compound.
• It contains the symbols of atoms of the elements present in the compound.
• As well as how many there are for each element, in the form of subscripts.

Explanation

Time is a scalar quantity because it only has magnitude (duration) but no direction.

Explanation

• Freezing is the process by which a liquid changes to a solid.
• It is the reverse of melting, which is the process by which a solid changes to a liquid.

Explanation

Inhibitors are molecules that decrease the activity of enzymes, often by binding to a specific site on the enzyme.

Activators are molecules that increase the activity of enzymes, often by binding to a specific site on the enzyme.

Explanation

A DC motor is an electrical machine that converts electrical energy into mechanical energy.

It uses electrical current to generate a magnetic field that interacts with the motor's magnets.

It causing the motor to rotate and produce mechanical energy.

Explanation

• H2 is only a homo atomic [homo: same] molecule.
• Rest three are hetero atomic [hetero: different] molecules).

Explanation

KCl (potassium chloride) is a salt.

Specifically a neutral salt formed by the reaction of an acid (HCl) with a base (KOH).

Explanation

Urea is a non-electrolyte, meaning it does not dissociate into ions in aqueous solution.

It does not conduct electricity.

Explanation

Ohm's Law is valid only if the temperature of the conductor remains constant.

If the temperature changes, the resistance of the conductor may change, and Ohm's Law may not hold.