past papers Flashcards
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
- 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
why is it safer for drivers to drive at a slower speed in wet weather
- less friction
- increases stopping distance (takes loner to slow down)
describe an investigation the students could carry out to show that momentum is conserved when two trolleys collide
- 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
give one reason for the runway being at a slope
- so it travels at a constant speed
describe how N’s 3rd law applies to the collision between the racket and the ball
- 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
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
- 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
what apparatus could you use to model the scattering of alpha particles
->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
what is a limitation of the marble-electron method
- not to scale
- marble has no charge
- not 3D
how are X-rays emitted
- 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
how are radio waves emmitted
- 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
what happens at the nucleus of an atom when a positron is emitted
- proton becomes
- a neutron
Explain why the refraction of the sound wave is different from the refraction of the light wave
- refraction is caused by a change in speed
- sound speeds up
- light slows down
if a ray goes towards the normal does this mean it sped up or slowed down
sped up
