Waves

Question 1

Explain briefly, in terms of the superpositions of waves, how the stationary wave is produced.

Answer 1

Waves reflected from each end interfere (to create maxima and minima)

Question 2

If the fundamental frequency of an oscillating string is 270Hz, what is the frequency of the 3rd Harmonic?

Answer 2

f3= 270 x 3 = 810Hz

Question 3

Two waves are coherent if…

Answer 3

They have a constant phase relationship

Question 4

For waves to have a constant phase relation ship they must:

Answer 4

Have the same frequency and wavelength

Question 5

What is brewsters angle? (Polarisation)

Answer 5

The angle at which reflected monochromatic light is 100% polarized.

Question 6

State what is meant by “plane-polarised light”

Answer 6

(The electric field vector oscillates in one plane only)

Question 7

Diameter of the smallest object that could be imaged by an OPTICAL microscope

Answer 7

398-410 nm

Question 8

1.5 eV (electron volts) =?

Answer 8

1.5 x (1.6x10^-19) (charge of an electron)

Question 9

State (2) pieces of experimental evidence of the particle like behaviour of waves

Answer 9

Compton scattering

The photoelectric effect

Question 10

State what is meant by quantum tunnelling.

Answer 10

A quantum particle can exist in a position that, according to classical physics, it has insufficient energy to occupy.

Question 11

State one piece of experimental evidence for a particle showing wave like behaviour.

Answer 11

Electron diffraction / interference

Question 12

Name the three types of damping

Answer 12

Lightly/underdamped
Heavily damped
Critically damped

Question 13

Outline the first steps to derive n=tan(ip)

Answer 13

n=sin01/sin01

=sin(ip)/sin(90-ip)

=sin(ip)/cos(ip)

Question 14

IMPORTANT thin film formula

Answer 14

2nd=m )\ (Or m + 1/2)

Question 15

Define damping in SHM

Answer 15

The rate at which amplitude is being reduced