3 2 reflection and refraction

True. Visible light is a transverse wave.

True. Light can undergo reflection and refraction.

Sound is a longitudinal wave.

The name given to the reflection of sound waves is an echo.

Yes, sound waves can be refracted.

The diagram represents a transverse wave.

The diagram represents a longitudinal wave, so it represents a sound wave.

Reflection is when a wave hits a boundary between two media and does not pass through, but instead stays in the original medium.

Refraction means a wave passes a boundary between two different transparent media and undergoes a change in direction.

The law of reflection states that the angle of incidence (i) is equal to the angle of reflection (r).

The angle of incidence is the angle between the incoming ray and the normal.

When light passes from air to glass, it slows down so it bends towards the normal.

When light moves from glass to air, it speeds up, so it bends away from the normal.

False. The frequency of light does not change during refraction. The wavelength and speed of light change during refraction.

In optics, a medium is a material that transmits light.

A ray diagram is a diagram used to show the direction of waves, with arrows indicating the incident and reflected/refracted rays.

When light passes along the normal into a transparent medium, it does not bend at all.

The light bends towards the normal when it passes between the boundary from air to glass as shown in the diagram because glass has a higher refractive index than air. The wave slows down and the wavelength increases.

The aim of the refraction core practical is to investigate the refraction of light using transparent rectangular blocks, semi-circular blocks, and triangular prisms.

The independent variable in the refraction core practical is the shape of the block.

The dependent variable in the refraction core practical is the direction of refraction.

One control variable in the refraction core practical is any one from:

A ray box is used to provide a narrow beam of light.

A protractor is used to measure the angles of incidence and refraction.

True. A sharpened pencil is used to accurately mark angles of incidence and refraction for the refraction core practical.

The purpose of a sheet of paper is to mark the lines indicating the incident and refracted rays.

A common systematic error in the refraction experiment is an error that occurs if the normal lines are drawn incorrectly.

A safety consideration that should be applied when using a ray box is to avoid looking directly at the light to prevent eye damage.

The refractive index is the ratio of the speed of light in a vacuum and the speed of light in a material.

True. Since the refractive index is a ratio, it has no units.

False. When the angle of incidence is less than the angle of refraction , or , the refracted ray bends away from the normal.

The equation for the refractive index is Where:

True. The value for the refractive index of a material will always be less than the speed of light in a vacuum.

The trigonometric function used in Snell's Law is sine.

True. When the angle of incidence is greater than the angle of refraction , or , the refracted ray bends toward the normal.

The equation for snell's law in terms of the refractive index is Where:

From the diagram, the angle of incidence is 39°.

From the diagram, the angle of refraction is 25°.

The aim of the Snell's law core practical is to investigate the refractive index of glass using a glass block.

The independent variable in the Snell's law core practical is the angle of incidence (i).

The dependent variable in the Snell's law core practical is the angle of refraction (r).

One control variable in the Snell's law core practical is any one from:

Snell's law is the ratio of the sine of the angles of incidence and refraction.

A protractor is used to measure the angles of incidence and refraction in Snell's law core practical.

The refractive index is determined by plotting a graph of sin(i) versus sin*(r *) graph and finding the gradient.

A common source of systematic error in the Snell's law core practical is drawing the normal lines incorrectly.

The safety measures that should be taken when using the ray box in Snell's law core practical are to avoid looking directly at the light to prevent eye damage.

The angles of refraction will be smaller than the angles of incidence because glass has a higher refractive index than air.

The critical angle is the angle of incidence that gives an angle of refraction of exactly 90°.

Total internal reflection (TIR) occurs when the angle of incidence is greater than the critical angle, and the ray is travelling from a denser material into a less dense material.

Total internal reflection is used to transmit information through optical fibre cables for television and internet communications.

The equation for the critical angle in terms of the refractive index is Where:

One application of total internal reflection is any one from:

False. Total internal reflection only occurs when light travels from a denser material into a less dense material.

The behaviour of the light ray at the glass-liquid boundary at X is defined as total internal reflection (TIR).

The second diagram shows the angle of incidence *i *equal to the critical angle c.