Y11 Physics

What is a magnetic field?

The space around a magnet where magnetic materials experience a non-contact force

Name some magnetic materials

Iron, steel, nickel, colbalt

Magnetic fields always go from what to what?

North to south

An un-magnetised magnetic material can be magnetised by being placed in a __________. This is called ______________

Magnetic field. Induced magnetism

What do you need to make an electromagnet?

Insulated wire (coiled), cell/power pack, iron core, switch

What is a solenoid?

A coil of insulated wire used to produce a magnetic field

How do you find the direction of magnetic fields?

Use the right-hand rules: Point your thumb in the direction of current, the curled fingers indicate the direction of the circular magnetic field lines

Where would the magnetic field lines go?

Towards B

What is wrong about this?

The person has pointed their thumb up when current flows down

What does each letter represent in the left hand rule?

F = Force, B = Magnetic field, I = Direction of current

What is the equation that links Magnetic Flux Density, Current, Force and Length?

Force = Magnetic Flux Density x Current x Length

What does a split ring commutator do?

Reverses the direction of the current around the coil every half turn of the coil

What direction with the left side of the coil go and which will the right side go to?

Left = Up
Right = Down

What is the method for the acceleration practical?

Set up a trolley on a runway attached by a string over a pulley to the hanger, release the trolley and use a light gate to record its velocity and time taken, redistribute masses and repeat.

What are the hazards in the acceleration practical?

Masses or trolley falling off the end onto feet → Use a stopper at the end of the runway

What are the variables in the acceleration practical?

IV: Force/Mass
DV: Acceleration
CV: Force/Total mass

What is the main source of error in the acceleration practical?

Friction between the trolley and the runway reduces the acceleration. Reduce it by tilting the runway slightly so the trolley moves at constant speed.