Electromagnetic waves and refraction

What is refraction?

Refraction is the bending of light or any wave as it passes from one medium to another.

How does the speed of light change when it enters a denser medium?

The speed of light decreases as it enters a denser medium, causing it to bend towards the normal.

What happens to light when it exits a denser medium into a less dense one?

The light speeds up and bends away from the normal.

What is the refractive index?

The refractive index is a measure of how much light slows down in a medium, defined as n=c/v, where c is the speed of light in a vacuum and v is the speed of light in the medium.

How do lenses use refraction?

Lenses use refraction to bend light and form images.

What is the critical angle?

The critical angle is the angle of incidence that results in light being refracted at 90° along the surface.

What is total internal reflection?

Total internal reflection occurs when light strikes a medium boundary at an angle greater than the critical angle, causing it to be completely reflected inside the medium.

What is the relationship between the refractive index and the angle of refraction?

A higher refractive index results in a smaller angle of refraction for a given angle of incidence.

How can you demonstrate refraction using a glass block?

Shine a light ray through a glass block and measure the angles of incidence and refraction as light enters and exits the block.

Why does a straw appear bent when placed in a glass of water?

Due to refraction, the light slows down and bends when it passes from water to air, making the straw appear displaced.

What is the speed of light in water?

The speed of light in water is approximately 2.25×10⁸ m/s.

How does the refractive index affect the bending of light?

A higher refractive index causes more bending of light when passing through a boundary.

What are the practical uses of refraction?

Refraction is used in eyeglasses, cameras, microscopes, and fiber optics.

What is the formula to calculate the refractive index?

The refractive index n is calculated using n=sin⁡I/sin⁡r, where i is the angle of incidence and r is the angle of refraction.