electromagnets and solenoids

Question 1

electromagnets are made of magnetically ____ materials

Answer 1

soft

Question 2

can electromagnets be made magnetic or non magnetic depending on what is needed, wanted

Answer 2

yes, if you turn the current off.

Question 3

what is a solenoid

Answer 3

a current carrying wire that has been wrapped into a coil

Question 4

inside of a solenoid, the magnetic field lines around each loop of wire line up with each other, this results in them,

Answer 4

being a lot of straight field lines that are all pointing in the same direction

Question 5

outside the solenoid, the magnetic field lines is like

Answer 5

one of a bar magnet

Question 6

does a solenoid have a north and south pole

Answer 6

yes

Question 7

for a solenoid to turn into an electromagnet, you must

Answer 7

put a block of soft iron in the middle of the coils

Question 8

if you add coils to a wire, the magnetic field strength

Answer 8

increases

Question 9

what is an electromagnet

Answer 9

a solenoid with a soft iron core

Question 10

when a block of soft iron core is placed in the centre of the coil, the magnetic field strength

Answer 10

increases

Question 11

why does the magnetic field strength increase when a soft iron core is added in he coils of a solenoid

Answer 11

because the soft iron core is easily magnetised by the solenoid and becomes an induced magnet when the current flows

Question 12

if you switch off the current, what happens to the magnetic field of an electromagnet

Answer 12

it disappears because the soft iron core is easily demagnetised

Question 13

properties of electromagnets (2)

Answer 13

• can switch them off and on quickly and easily
• can be made a lot stronger than permanent magnets because you can change their strength by changing the current

Question 14

do permanent magnets need current to work

Answer 14

no because they always produce a magnetic field