Paper 2 correction

Question 1

(ii) Show that the SI base units of power are kg.m^2.s^-3.

.

Answer 1

power = work done / time taken
= (force x distance)/ time taken
= (kg.m /s^3)(m) / s
= kg.m^2.s^-3

Question 2

Derive, from the definitions of pressure and density, the equation
p = ρgh
where p is the pressure exerted by the liquid on the base of the container and g is the
acceleration of free fall.

Answer 2

ρ = m/Ah & p = W / A

P = ρgh

Question 3

(ii) State and explain the changes in energy that occur as the sphere falls.

Answer 3

When gravitational potential energy decreases, it causes the thermal energy to increase.

Question 4

Use your answer in (ii) to determine

1. the electric field strength, 9702/23/O/N/17

Answer 4

E = F/Q = (6.68X10^-15) / (1.6 X 10^-19) = 4.2X10 ^4

Question 5

2. the potential difference V between the plates. 9702/23/O/N/17

Answer 5

E = V/ distance between plates.

Question 6

State one similarity and one difference between a β+ particle and a β- particle.

Answer 6

similarity: same (rest) mass / equal (magnitude of) charge
difference: opposite (sign of) charge / one is matter and one is antimatter / one is an electron and one is an antielectron