2020 Paper 2 (7/02/2025)

Question 1

Energy transferred in changing state effecting atom arrangement?

Answer 1

A constant temperature signifies the change in state. Atoms can move their centre of vibration. Some atomic bonds are broken between atoms with energy supplied. Crystalline structure changes to amorphous . Atoms can now move past each other rather than vibrate around a fixed position.

Question 2

Potential and Kinetic Energy at latent heat?

Answer 2

Kinetic energy remains constant and the potential energy increases, whilst at a constant temperature

Question 3

Energy between changing state and latent heat?

Answer 3

There is a temperature change in this phase meaning the mean speed and mean kinetic energy increases

Question 4

Electric Field lines and force?

Answer 4

Electric Field lines show the direction of force from the electric field upon a positive charge

Question 5

Accelerated Charged Particle Equation?

Answer 5

eV = 1/2 m v ^2

Charge x Potential Difference = 1/2 x mass x velocity ^2

Question 6

Time intervals showing different masses?

Answer 6

A smaller mass gives a smaller time interval. This is because both ions show they’re given the same force. So, smaller mass has a higher acceleration which explains smaller time interval. Charge and potential difference is constant which means kinetic energy gained is the same. Smaller mass gives a greater speed which explains smaller time interval.

Question 7

Y-voltage gain meaning?

Answer 7

The scale in division (squares) of the y-axis on the screen of the oscilloscope

Question 8

Trace output of DC supply on oscilloscope?

Answer 8

Its a straight line at the Vrms value on the y-axis

Question 9

Time constant in terms of voltage?

Answer 9

Time constant is the time for voltage to get to 37%

Question 10

Control settings on oscilloscope to reduce uncertainty in time constant?

Answer 10

Reduce the time base to make resolution smaller and more accurate value of “t” obtained. Alternatively, y-gain can be reduced to make resolution smaller and more accurate values of “V” obtained. More accurate readings have lower uncertainty because the margin of error is smaller for each value and more resolution makes larger values and as this is smaller makes uncertainty less

Question 11

Fundamental force involved when alpha particle scattered upwards?

Answer 11

Electromagnetic Force

Question 12

Rate of change of momentum of alpha particle deflecting away from gold nucleus?

Answer 12

Rate of change of momentum is another name for force and since the gold nucleus and alpha particle are positive it means this rate of change of momentum will vertically away from the nucleus

Question 13

If an alpha particle came to rest what equation would be used?

Answer 13

KE = PE
1/2 m v ^2 = 1/4𝜋𝜀0 x Qq / r^2

Question 14

Nuclear Radius Equation?

Answer 14

R = R0 x A ^ 1/3
Where “r” is nuclear radius, “r0” is a constant, “A” is the atomic number

Question 15

Conclusion if all nuclei have approximately the same density?

Answer 15

Nucleons are incompressible, nucleons have constant separations, neutrons and protons have similar masses and volumes

Question 16

If a thermal nuclear reactor has fuel in ratio U-235 and U-238 how do neutrons interact with these nuclei?

Answer 16

U-235 absorbs a neutron to become U-236 which is unstable and decays into 2 daughter nuclei and 2/3 neutrons. Whereas 238 absorbs neutrons without fission and scatters neutrons

Question 17

Equation to compare masses of nuclear sample?

Answer 17

M / M0 = e - λt where “M” is the current mass, “M0” is the original mass, “t” is the time between “M” and “M0”, and “λ” is the decay constant

Question 18

How to go from degrees to kelvin?

Answer 18

+273

Question 19

No net transfer of particles meaning?

Answer 19

This means pressure is constant

Question 20

Brownian motion cause?

Answer 20

The motion is caused by collisions between air molecules and smoke particles

Question 21

Time Period of geostationary orbit around Earth?

Answer 21

24 hours otherwise 86400 seconds

Question 22

Parallel equipotential lines?

Answer 22

This would signify a uniform field

Question 23

Point Charge equipotential lines?

Answer 23

Circular and the lines become more spread out further away from the point charge

Question 24

Force, Current for vertical square coil perpendicular to a uniform horizontal magnetic field?

Answer 24

On the vertical sides of the coil the current will be in opposite directions resulting in the forces also being in opposite directions

Question 25

EMF at maximum flux linkage?

Answer 25

There will be no EMF at the maximum flux linkage

Question 26

EMF alternative meaning in terms of rate of change?

Answer 26

EMF is the rate of change of flux otherwise EMF = change in B x Change in Area / change in distance

Question 27

Rate of Decay is proportional to?

Answer 27

Rate of decay otherwise activity is proportional to the number of atomic nuclei and this is shown by the equation: A =λN