AS Weaknesses

Question 1

Define EMF

Answer 1

Work done in moving 1 C of charge whole way round circuit

Question 2

Series and Parallel Circuit rules:

Answer 2

Series
Total P.D is shared
Current is same for all components
Total Resistance

Parallel
P.D is the same for each branch
Current is split between branches
Adding more resistors in parallel REDUCES total R

Question 3

Total Internal Reflection Notes:

Answer 3

TIR occurs when incident angle is higher than critical angle. So all light reflects.

Light must be in the medium with the higher refractive index

Question 4

Optic Fibre notes:

Answer 4

(Inside to out)
Core
Cladding
Protective sheath

Material Dispersion:
The spreading of a light pulse traveling through an optical fibre due to the different wavelengths of light within the pulse traveling at slightly different speeds.
Eg. blue light travels slower than red light.

Modal Dispersion:
Light pulses broaden due to different modes of light taking different paths through the fibre. (Hence taking more time)

Solve Modal Dispersion by:
Thinner core
Put repeaters in every so often.

Question 5

Polarisation Notes:

Answer 5

Unpolarised light waves:
Oscillations (or vibrations) of particles /
fields perpendicular to direction of energy
Transfer. (Transverse)

• wave’s oscillations (or vibrations) exist in
  more than a single plane

A polarising lens filter absorbs light:
If filter has horizontal filter lines then waves oscillating vertically are absorbed and horizontal oscillating lines pass through.

Longitudinal waves cannot be polarised (Evidence that EM waves are transverse)

Question 6

Define Photon

Answer 6

Discrete Packets of light

Question 7

Strangeness rules:

Answer 7

Any interaction involving leptons are the weak interaction

If ONLY hadrons involved and strangeness conserved than STRONG interaction

Question 8

Define Isotope
Nucleon

Answer 8

Isotope: Same element, Same protons different neutrons.

Nucleon: A proton or neutron in the nucleus

Question 9

Need for the neutrino?

Answer 9

Used to account for the conservation of energy in beta decay

Question 10

Define Stopping Potential
Work Function
Threshold Frequency

Answer 10

Stopping Potential
potential difference required to stop photoelectrons from reaching the anode in the photoelectric effect experiment.
Used to calculate KE of the electrons

Work Function
The minimum ENERGY required to release a photoelectron from the surface of a metal

Threshold Frequency:
Minimum FREQUENCY required to release a photoelectron from the surface of a metal

Question 11

Moment Definition

Answer 11

Force x perpendicular distance from the point to the line of action of the force.

Principle of couple of moments
F x perpendicular distance between lines of action of the forces.