past papers

Question 1

what should a diagram to show how copper cans with the materials sand and sawdust look like when finding out which material is the better insulator

Answer 1

• small copper can inside large copper can
• hot water with thermometer in the water
• insulated material in large copper can but outside of small copper can

Question 2

why is it safer for drivers to drive at a slower speed in wet weather

Answer 2

• less friction
• increases stopping distance (takes loner to slow down)

Question 3

describe an investigation the students could carry out to show that momentum is conserved when two trolleys collide

Answer 3

• measure mass/ weigh trolleys
• determine speed of trolleys
• put one light gate (connected to data logger) further down the runway then trolley A and another beyond trolley B
• trollies A and B stick together
• measure combined speed of trolleys
• calculate momentum of trolley A before collisions AND A and B after collision
• repeat AND take average

Question 4

give one reason for the runway being at a slope

Answer 4

• so it travels at a constant speed

Question 5

describe how N’s 3rd law applies to the collision between the racket and the ball

Answer 5

• forces are equal/same size
• forces in opposite direction
• forces act on different bodies
• ## same type of forceadditional guidance
• no marks for answers in terms of energy
• forces are one to left and one to right
• one force acts on racket one on ball
• both are contact forces

Question 6

explain how the difference in the number of particles scattered at different angles gives evidence for the current model of the structure of the atom

Answer 6

• observations
  -> most alpha paticles pass striaght through foil with little deflection
  -> some alpha particles are scatteres/deflected through small angles
  -> few alpha particles arae scattered/deflected through large angles
• conclusions
  -> atoms are mainly empty space
  -> there must be a nucleus
  -> nucleus must be small/concentrated

Question 7

what apparatus could you use to model the scattering of alpha particles

Answer 7

->apparatus
- large sheet of paper iwht lines centimeters apart
- circular weight
- movable slope for marble to roll down
-> how to use
- roll marble down slope
- record where marbles go OR meausre angle of path

Question 8

what is a limitation of the marble-electron method

Answer 8

• not to scale
• marble has no charge
• not 3D

Question 9

how are X-rays emitted

Answer 9

• when electrons change energy levels
  -> BECAUSE
  -» electrons in lower energy levels absorb energy
  -» so they move up to higher energy levels
  -» when they go bacl to lower levels they lose energy as radiation
  -» the electrons need to lose a large amount of energy
  -» so that they emit X-ray radiation so high frequency/energy

Question 10

how are radio waves emmitted

Answer 10

• when electrons oscillate in electricla circuits
  -> OSCILLATIONS ARE
  -» current (flow of electrons) that coninually change direction
  -» current flows up and down in a transmitting aerial
  -» alternating current
  -» this generated radio waves in the air arounf the aerial
  -» the frequency of the radaio waves correpsonds to the oscillation frequency