Topic 10 - Light and sound

Question 1

What is light? (4)

Answer 1

• Energy
• Wave (Electromagnetic)
• Photons (packets of energy)
• Light is a type of transverse wave

Question 2

What is refraction?

Answer 2

Refraction is the bending of light when it travels from one medium to another.

Question 3

How does light travel?

Answer 3

Light travels along a straight line in a medium

Question 4

What speed does light travel in at a vaccum?

Answer 4

Light travels at a speed of 3 x 108 m/s in vacuum

Question 5

Why does REFRACTION happen? (2)

Answer 5

• Refraction is is due to change in speed of light when it travels from one medium to another.
• Wavelength of light changes when light travels from one medium to another. Frequency of light does not.

Question 6

What is reflection?

Answer 6

The phenomena of bouncing of the light waves from a surface into the same medium is known as reflection of light

Question 7

2 types of reflection

Answer 7

• regular reflection
• diffuse reflection

Question 8

Regular reflection?

Answer 8

Reflection from a smooth, flat surface is calledregular reflection. This is the type of reflection that happens with a flat mirror.

Question 9

Diffuse reflection?

Answer 9

If a surface is rough,diffuse reflectionhappens. Instead of forming an image, the reflected light is scattered in all directions.

Question 10

Laws of reflection (2)

Answer 10

• Angle of incidence = Angle of reflection
• Incident rays, normal, point of incident, reflected rays all lie on the same plane

Question 11

Formula for relfraction?

Answer 11

sin(i) x n1 = sin(r) x n2

Question 12

transverse wave

Answer 12

A wave in which the oscillations are perpendicular to the direction of energy transfer

Question 13

longitudinal wave

Answer 13

A wave in which the oscillations are parallel to the direction of energy transfer

Question 14

wave speed?

Answer 14

= frequency x wavelength

Question 15

frequency?

Answer 15

= 1/time period