Paper 2 Questions Misconceptions

Question 1

Uncertainty greater than smallest division?

Answer 1

There are 2 lots of uncertainty on the measurement, as the uncertainty of the 2 readings is added it means uncertainty is greater than the smallest division

Question 2

Adding or subtracting uncertainty method?

Answer 2

(Uncertainty in readings / Values total) x 100

Question 3

Percentage uncertainty in 2 values compared to 1?

Answer 3

Fewer readings to get the same value. This means the amount of uncertainty is smaller as it is over a larger value.

Question 4

Wavelength percentage uncertainty reduction?

Answer 4

A larger distance to the screen increases fringe spacing which increases wavelength and a larger value lowers uncertainty

Question 5

Ohms Law?

Answer 5

The point at which voltage and current remain proportional with each other

Question 6

Factors affecting if circuit can obtain current-voltage data?

Answer 6

Ammeter not being in series, voltage ranges being too high from components placement, voltmeters have to be in parallel to what they’re measuring

Question 7

Beta Plus decay?

Answer 7

A proton turns in a neutron due to an up quark decaying into a down quark

Question 8

Why are photons on gamma detector opposite each other?

Answer 8

Momentum is conserved when a photon pair is released in equal and opposite directions

Question 9

What does increased reflectance of particles do to the reflecting surface?

Answer 9

A higher number of photons are reflected, a greater impulse is produced from reflection or absorption of particles, the impulse causes a greater acceleration of the surface

Question 10

Why is a thermistor preferred to a fixed resistor?

Answer 10

Fixed resistor will mean current is reduced at all times, thermistor has more current during surge so receives a greater voltage and is more efficient, fixed resistor has higher resistance at increasing temperature

Question 11

KE units?

Answer 11

kg m^2 s-2

Question 12

Young’s modulus units?

Answer 12

kg m-1 s-2

Question 13

Isotopes drawn on graph?

Answer 13

Z axis will be constant for all points whereas N has points going up or down. This produces a straight line down.

Question 14

Positive Pion property?

Answer 14

Has to have an up quark

Question 15

What are the properties of a muon?

Answer 15

Lepton so not subjected to strong interactions, a muon is required if it decays into an electron, not a stable lepton as it can decay into an electron

Question 16

What is the difference between red and green light?

Answer 16

Red light has a higher wavelength which means it has a lower frequency and less energy for colour photons it emits

Question 17

What is the method for working out the pulse of a wave?

Answer 17

Work out the wavelength of the pulse. Multiply this by the amount of wave cycles the pulse produces

Question 18

What is the order of the EM spectrum in order of increasing wavelength?

Answer 18

Gamma -> X-Ray -> UV -> Visible -> Infared -> Microwave -> Radio

Question 19

Highest maximum angle?

Answer 19

sin(90)

Question 20

Equilibrium force direction?

Answer 20

The downwards force will be the same as the upwards force

Question 21

Total Moments?

Answer 21

These are found from the resultant of the left moment taken away from the right hand side moment

Question 22

Relationship between elastic collisions and kinetic energy?

Answer 22

KE decreases when objects stick together in an elastic collision, KE conserved when objects don’t stick to each other in an elastic collision

Question 23

What is the factor change of length doubling and diameter halving L/d^2 ?

Answer 23

8

Question 24

What is the significance of 10 kV?

Answer 24

It is the potential difference of the whole national grid so cannot be used if a section using it is being solved

Question 25

How to work reading of a voltmeter in series with negligible internal resistance?

Answer 25

Multiply the total resistance by the EMF to get voltmeter reading

Question 26

Another name for internal resistance?

Answer 26

Load Resistance