physics paper 3 Flashcards
(14 cards)
What is the difference between repeatable and reproducible?
Repeatable means the SAME method, SAME variables, SAME person, Reproducible means a DIFFERENT method, DIFFERENT variables and a DIFFERENT person doing the experiment
Which way does current flow through a diode?
The open side of the triangle
Which changes of state absorb energy?
Low to High (Evaporating, Melting, Sublimating)
Why does temperature increase when work is done on a gas?
Work is done on the gas, so the speed of particles increase, meaning more frequent collisions. This results in a rise in temperature, and energy is transferred from a kinetic energy store to a thermal energy store.
Why do some objects float?
The force of the upthrust pushing the object upwards is EQUAL to the weight of the object // object is LESS dense than the liquid
Why does a coil rotate when a current passes through it?
Current in a coil creates a magnetic field (electromagnetic induction). This field interacts with the magnet’s magnetic field, creating a force - one side upwards, one side downwards
Why does a moving object reach a maximum velocity?
As velocity increases, air resistance also increases - Until weight balances air resistance - so there is no resultant force, and no acceleration (maximum velocity)
How do you know an object stretches?
TWO DIFFERENT forces are acting on it
How does the resultant force act when an object is moving in a circular path at a constant speed?
Towards the centre of the circle
What is a microphone?
A device that converts sound waves into electrical signals
What is a loudspeaker/headphones?
A device that converts electrical signals into sound waves
How does a transformer work?
- Uses AC , so alternating p.d on primary coil produces alternating current on secondary coil.
- AC in secondary coil produces a changing magnetic field in iron core
- Induces changing p.d in secondary coil
How does a microphone work?
- Generator Effect (movement produces p.d/current)
- Pressure variations of sound waves hit diaphragm, causing movement of coil
- Movement produces a p.d across wire, producing the electrical signal
How does a loudspeaker/headphone work?
- Motor Effect (p.d/current produces movement)
- AC to the coil creates a changing magnetic field, which interacts with magnet’s magnetic field, producing a force.
- Coil moves due to this movement, so cone vibrates.
- Vibrating cone causes pressure variations, generating sound waves.
