waves (basic and refraction)

Explain what is a progressive wave and examples

Transfer of injury as a result of oscillation. All points on a progressive wave have a different phase within one wavelength.

Examples are mechanical, longitudinal or transverse

What is a stationary wave and state examples?

Trapped entry in pockets between notes. No net energy transfer therefore no transfer of information.

Examples are mechanical, longitudinal and transverse

What are mechanical ways in state examples?

Waves which need a medium (material) Through which to travel

E.g sound and seismic

What is a longitude on a wave? Explain explained its motion and its examples

Particles of the medium oscillate parallel to the direction of energy transfer

E.g sound

Since it is parallel, if you move it front to back, the energy will also be moving forward

What is a transverse wave state examples and explain its motion?

Particles of the medium oscillate perpendicular to the direction of energy transfer. All transverse waves can be polarised.

E.g all electromagnetic waves

Since it is perpendicular if you are moving up and down, the energy will be transferring forward

What is wave speed and how can you calculate it

Distance travelled by the wave and per unit time

V=f x lamda (wavelength)

Or c= f x lamda

Where c= 3×10^8, speed of light in a vacuum of all electromagnetic waves

What is frequency and how can you calculate it?

What is time period and how can you calculate it?

Frequency is the number of oscillations per unit time

F=1/T

Time period is the time taken for one complete oscillation of point in a wave

T=total time/no. Of complete wavelengths

What is phase difference and how can you calculate it?

The fraction of an oscillation between two particles or points in a wave

In radians: path diff/lamda x 2pi

In degrees: path diff/lamda x 360

State the electromagnetic spectrum, low frequency to high frequency, long wavelength to short wavelength

State the order of visible light and the state longest the shortest wavelength

Radio wave, microwave, infrared radiation, visible light, ultraviolet, x-rays, gamma rays

Low frequency to high frequency

Long wavelength to short wavelength

Red, orange, yellow, green, blue, indigo, violet

Long to short

State the wavelength of the electromagnetic spectrum in metres

Gamma=-16 to -10

X-ray=-13 to -8

Ultraviolet=-8 to 4×10^-7

Visible= 4×10^-7 to 7×10^-7

Infrared=7×10^-7 to 10^-3

Microwave= -3 to -1

Radio= -1 to 6

What is the definition of reflection?

Angle of incidence is equal to the angle reflection of wave energy

Theta 1=theta 2

What is the definition of refraction?

Wave energy transmitted into another medium

The changing optical density = the change in speed therefore change in direction

Using the wave speed equation, What properties stay the same and what change?

V=f x wavelength

Frequency is fixed, therefore the wavelength and the speed will change

What happens to the wave energy when it enters a higher optical density?

The wave shows down therefore bent towards the normal therefore the angle of incident is smaller than the angle of reflection

Theta 1 is less than theta 2

What happens when a wave enters a lower optical density?

The waves speeds up therefore bends away from the normal therefore the angle of incident is larger than the angle of reflection

Theta 1 is more than theta 2

What is snell’s law and what is its equation?

Ratio of the signs of an angle of incident and refraction is equivalent to the ratio of refractive index which is also equivalent to the ratio of velocities and the two mediums

Sin theta 1/ sin theta 2

=n2/n1

=v1/v2

What is the total internal reflection?

That is when light meets an optically less dense medium

It also means when the angle of incident is less than the critical angle

How do you calculate the critical angle?

Sin^-1 (n2/n1)

What does the angle of refraction equal to if the critical angle is equal to the angle of incidence

90*