Answers Flashcards
Q1)how does L and T oscillate (2)
L- ossolates parallel to direction of travel of wave
T- ossolates perpendicular to direction of travel of wave
1)b)i) what is the amplitude? (1)
40mV
1)b)ii) work out frequency (2)
Period= 1.5ms, frequency + 1/period= 1/1.5»_space;»=667Hz«
1)B)iii) work out wavelength (1)
330/667 = 0.49m
1)c) (2) is the period the same
Intensity is proportional to amplitude squared so Same period (idk)
2)a)i) what is the principal of superposition (1)
When two or more waves overlap, the resultant displacement at a point is equal to the vector sum of the individual displacements.
2)a)ii) what is coherent (1)
Constant phase difference
2)b)1/2) path difference (2)
1= 1 lambda 2= 1.5 lambda
2)c) if A increases what will happen (2)
Lambda and D are constant so if A is increased separation of max increase
3)a)i) suvat question (1)
V=u+at so t= 6.3/9.81 = 0.642s
3)c) air resistance question (2)
With air resistance; reaches lower max height; will reach max height before hits wall; same initial path
4)c) (4) PD changes
ldr will decrease so total resistance in circuit is less so current increases. So PD across 1.2k will increase, so PD across DR must decrease (PDs add up to 6v)
5)b)i) (1) why use putty
So that the current flows through All cross sectional area of the putty
5)b)ii) (2) experiment
Use micrometer at different points and different orientations
Use a template with hole of correct diameter and extrude
5)c)i) (1)
6.6
5)c)ii) (1) percentage uncertainty
Percentage uncertainty in L= 0.001/0.049 X 100= 2%
So percentage uncertainty in L^2= 2 x 2.0= 4%
5)d)i) graph (2)
Plot point and draw line of best fit (NOT through false origin)
5)d)ii) work out gradient (2)
5.7 ish
6)a) on the wire pag thing with Steve (6)
- Wear safety glasses in case wire whiplashes in eyes
- Place cushion (soft thing) under load so it doesn’t break anything when it breaks
- Measure average diameter of wire in serval places using micrometer
- calculate cross sectional area = pi x (d/2)^2
- hang load off wire
- add weights one at a time until breaks, record breaking mass
- breaking stress= mass x 9.81 / cross sectional area
6)b) (2) glass and rubber
Glass= straight line - steep Rubber= curves - lower line when unloaded
Q7)a) (6) photo electric effect
- One photon is absorbed and may release one electron if frequency of light is above threshold frequency of metal then electrons are emitted.
- UV has a higher frequency than visible
- E=hf so UV have more energy
- if Energy of photons is bigger than the work function energy of metal electrons are emitted.
- UV has enough energy, visible doesn’t
- when electrons are emitted change on electroscope drops and leaf falls because they aren’t repelling eachother
8)c) (2) light experiment
- Rings will be close together and brighter
- Higher PD= more energy= greater V= smaller wavelength
