Explanation

 Those substances through which electric current cannot pass are called insulators.

Insulators have very high electrical resistance

. For example, wood, rubber, glass, paper, plastic and wax are insulators of electricity.

Insulators cannot conduct electricity due to absence of free electrons in them.

Explanation

The force on a moving charge in a uniform magnetic field depends on:

• Magnetic flux density (B): The strength of the magnetic field.
• The charge on the particle (q): The amount of charge on the particle.
• The speed of the particle (v): The velocity at which the particle is moving.

The force (F) on a moving charge in a uniform magnetic field is given by the Lorentz force equation: F = q (v x B)

Where x denotes the cross product.

Explanation

Heat conduction is a process in which heat is transferred from the hotter part to the colder part in a body without involving any actual movement of the molecules of the body.

AGM 25-12-2022

Explanation

Very high frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz,

with corresponding wavelengths of ten to one meter.

ND17-7-2023

Explanation

Progressive waves are waves that transfer energy from one point to another through a medium, such as a solid, liquid, or gas.

They are also known as mechanical waves, and examples include:

• Water waves
• Sound waves
• Seismic waves (earthquakes)

Explanation

A hydrogen-filled balloon expands as it rises and may even burst after rising very high in the atmosphere

As one goes high, the weight of the atmosphere above decreases and so does the pressure.

Thus for a balloon filled on the ground, the pressure inside the balloon exceeds that outside and thus it bursts.

Explanation

The force exerted on a charged particle by a magnetic field is perpendicular to both the magnetic field and the velocity of the particle. This is described by the Lorentz force equation: F = q (E + v x B)

Where:

• F is the force
• q is the charge
• E is the electric field
• v is the velocity
• B is the magnetic field
• x denotes the cross product

The cross product of two vectors results in a vector that is perpendicular to both of the original vectors.

Therefore, the force due to the magnetic field and velocity is at right angles to each other.

Explanation

Conduction is heat transfer through stationary matter by physical contact. 

Convection is the heat transfer by the macroscopic movement of a fluid.

Heat transfer by radiation occurs when microwaves, infrared radiation, visible light, or another form of electromagnetic radiation is emitted or absorbed.

Explanation

The phenomenon of refraction of light is the shift in the path of light as it travels from one medium to another

Explanation

In p-type semiconductors, a trivalent impurity is added, typically Boron.