KEY EQUATIONS

Question 1

Lateral Magnification

Answer 1

M=y’/y

M magnification
Y’ image height
Y object height

If m>1 Image is magnified
If m<1 Image is demagnified

If m is positive, Image is upright
If m is negative, Image is inverted

Question 2

Focal length for a spherical mirror:

Answer 2

Half of the radius of curvature for a spherical mirror.

f= 0.5R concave
f= -0.5R convex

Question 3

The mirror equation:

Answer 3

1/s + 1/s’ = 1/f

S distance from object to mirror
S’ distance from Image to mirror
F mirror focal length

m=-s’/s

Question 4

Lensmakers Equation:

Answer 4

1/f = (n-1)(1/R1 - 1/R2)

f focal length
n Refractive index
R1 Radius of first curvature
R2 Radius of second curvature

If f is positive, converging lens
If f is negative, diverging lens

Question 5

F-number (light gathering capacity) of a lens:

Answer 5

Focal length/aperture diameter

f/D

Question 6

Angular magnification for a simple magnifier:

Answer 6

M= theta’/theta= (y/f)/(y/25) = 25cm/f

Question 7

Overall angular magnification for a microscope:

Answer 7

Lateral magnification*Angular Magnification

25cm*s’/f1f2

Question 8

Overall magnification for a telescope:

Answer 8

-f1/f2

Question 9

Numerical Aperture:

Answer 9

=nsinalpha

N refractive index
Alpha angle

Question 10

Apparent depth can be found using:

Answer 10

Na/s + Nb/s’ = Nb-Na/R

Question 11

Double slit

Answer 11

Ym=R (mlambda)/d

Question 12

Amplitude in two source interference

Answer 12

Ep = 2E|cos(phase angle/2)|

Question 13

Intensity in two source interference

Answer 13

I0cos^2 phase angle/2

Question 14

Phase difference

Answer 14

2pi/lambda * path difference

Question 15

Constructive reflection thin film

Answer 15

2t=mlambda

Question 16

Destructive reflection thin film

Answer 16

2t= (m+0.5) lambda

Question 17

Constructive reflection thin film with phase shift

Answer 17

2t=(m+0.5) lambda

Question 18

Destructive reflection thin film with phase shift

Answer 18

2t=m lambda

Question 19

Gamma

Answer 19

1/SQRT(1- u^2/c^2)

Question 20

Time dilation

Answer 20

Gamma*proper time

Question 21

Length contraction

Answer 21

Proper length/gamma

Question 22

Lorentz coordinate transformations

Answer 22

x’=gamma(x-ut)

t’=gamma(t-ux/c^2)

Question 23

Doppler effect

Answer 23

f=SQRT(c+u/c-u f0)

Question 24

Relativistic momentum

Answer 24

P=mv*gamma

Question 25

Relativistic kinetic energy

Answer 25

(Gamma-1)mc^2

Question 26

Total energy of a particle

Answer 26

Gammamc^2

Question 27

Total energy, rest energy, momentum

Answer 27

E^2 = (mc^2)^2 + (pc)^2

Question 28

Photoelectric effect

Answer 28

eV0=hf - phase angle

Question 29

Momentum of a photon

Answer 29

P= E/c=hf/c=h/lambda

Question 30

Brehmsstrahlung

Answer 30

eV=hf=hc/lambda

Question 31

Compton scattering

Answer 31

Lambda’-lambda= h/mc (1-cosangle)

Question 32

De Broglie wavelength of a particle

Answer 32

Lambda = h/p = h/mv

Question 33

De Broglie wavelength of an electron

Answer 33

Lambda = h/p = h/SQRT(2meV)

Question 34

Energy of an emitted photon

Answer 34

Hf=hc/lambda = Ei-Ef

Question 35

Quantisation of angular momentum

Answer 35

L=mvr= n h/2pi

Question 36

Orbital radii in the Bohr model

Answer 36

Rn= epsilon0 n^2h^2/pime^2

Question 37

Orbital speeds in the Bohr model

Answer 37

Vn = 1/epsilon0 e^2/2nh

Question 38

Total energies in the Bohr model

Answer 38

Rn = n^2a
En= -hcR/n^2
R= me^4/8*epsilon^2*h^3*c

Question 39

Stefan-Boltzmann for blackbody

Answer 39

I=SBC*T^4

Question 40

Wein displacement law

Answer 40

LambdaT = 2.910^-3

Question 41

Planck radiation law

Answer 41

I= (2pihc^2)/[lambda^5(e^(hc/lambdakt) -1)]