Explanation

Metals are good conductors of electricity because they have free electrons, also known as conduction electrons or mobile electrons.

These electrons are not tightly bound to a specific atom and are free to move throughout the metal, carrying electrical current.

Explanation

The correct answer is: Light waves, Radio waves, Microwaves

This group consists only of electromagnetic waves, which are waves that propagate through the electromagnetic field.

They do not require a physical medium to propagate.

Explanation

Harvesting is the most important step in the preparation of sugar from sugarcane or sugar beets.

Sugarcane is typically harvested by hand or by machine, and sugar beets are harvested by machine.

The quality of the harvest affects the quality of the sugar produced.

Explanation

Accuracy refers to how close a measured value is to the true or accepted value.

It indicates the degree of agreement between the measured value and the true value.

Explanation

A reversible reaction is a reaction that can proceed in both the forward and reverse directions, and never goes to completion.

It is represented by a double arrow (⇌) between the reactants and products.

For example: A + B ⇌ C + D

Key Point:

• Single arrow (→): Represents an irreversible reaction, where the reaction only proceeds in one direction.

Explanation

The direction of induced e.m.f. (electromotive force) in a circuit is determined by Lenz's law.

It states that the induced e.m.f. will oppose the change in magnetic flux that induced it.

This is a consequence of the conservation of energy.

Explanation

Magnetic poles always exist in pairs, with every magnet having a north pole and a south pole.

Like poles (north-north or south-south) repel each other.

Unlike poles (north-south or south-north) attract each other.

Explanation

Electromagnetic waves are typically listed in order of increasing wavelength (or decreasing frequency) as follows:

• Gamma-rays (shortest wavelength, highest frequency)
• X-rays
• Microwaves (longer wavelength, lower frequency)

Explanation

Sound is a form of mechanical energy that is produced by vibrations or oscillations of particles in a medium, such as air, water, or solids.

When an object vibrates, it creates a disturbance in the medium around it, causing the particles to oscillate back and forth.

This oscillation, or wave motion, is what we perceive as sound.

Explanation

In gas chromatography (GC), the mobile phase is a gas, such as helium, nitrogen, or argon, that carries the sample through the column.

The sample is vaporized and separated based on its affinity for the stationary phase, which is typically a solid or liquid coating on the column.