4- Oscillations and Waves

Question 1

Energy SHM

Answer 1

1/2mω^2x

Question 2

Refractive index

Answer 2

Speed of wave in medium 1 ÷ speed in medium 2

Question 3

Red light wavelength

Answer 3

700 nanometres

Question 4

Blue light wavelength

Answer 4

500 nanometres

Question 5

Radio Micro Infrared Visible UV X Gamma

Answer 5

Electromagnetic spectrum

Question 6

Simple harmonic motion

Answer 6

Motion where the acceleration of an object is directed towards a fixed point and is proportional to its displacement from that point.

Question 7

Simple harmonic motion (equation)

Answer 7

a = −w^2x

Question 8

Critically damped

Answer 8

Damping causes SHM to rapidly die away in the minimum time without completing an oscillation (like immersing in honey)

Question 9

Longitudinal travelling wave

Answer 9

Direction of oscillation of particles is in direction of energy propagation

Question 10

Amplitude (definition)

Answer 10

Maximum displacement from the mean

Question 11

Angular frequency (equation)

Answer 11

ω=2π/T

Question 12

Compressions

Answer 12

Points on a longitudinal wave where the particles are ‘bunched together’

Question 13

Constructive interference

Answer 13

When two identical waves meet at a point and the waves are exactly in phase, the resulting wave has twice the amplitude of either of the original waves

Question 14

Crest

Answer 14

The peak of a transverse wave (the point of maximum positive displacement)

Question 15

Damping

Answer 15

Involves a force that is always in the opposite direction to the direction of motion of the oscillating particle and is a dissipative force (i.e. the oscillating particle loses energy)

Question 16

Destructive interference

Answer 16

When two identical waves meet at a point and the waves are exactly (180°) out of phase, the resulting wave has zero amplitude – the two waves cancel each other

Question 17

Gamma rays

Answer 17

10^-15 - 10^-10 m

Question 18

Diffraction

Answer 18

The spreading of a wave past an aperture or obstacle.

For this to be observable, the size of the obstacle or gap needs to be the same order of magnitude as the wavelength

Question 19

X-rays

Answer 19

10^-10 - 10^-8 m

Question 20

UV

Answer 20

10^-8 - 10^-7 m

Question 21

Visible

Answer 21

400 nm - 700 nm

Question 22

Infrared

Answer 22

10^-6 - 10^-3 m

Question 23

Microwave

Answer 23

10^-3 - 10 m

Question 24

Radio

Answer 24

10 - 10^5 m

Question 25

Frequency

Answer 25

Number of completed oscillations in a given period of time

Question 26

Intensity (definition)

Answer 26

The power per unit area of a wave that is received by the observer.

Question 27

Intensity (equation)

Answer 27

I = p/A