Transcript the strength of an electromagnet depends on the current

1. A current of 2 A flows through a filament
lamp. If the voltage across is 6 V,
calculate its:
a. Power.
b. Resistance.
(Equations P =VI, R = V/I)
2. This question is about current.
a. Name an appliance used at home
which makes use of the heating
effect of the current.
b. What is the difference between
alternating current and direct
current?
3. An electric blanket of power 200 W is
used for 6 hours. If 1 kWh costs 10 c,
calculate the:
a. Electrical energy used in kWh.
b. cost in cents.
(Equations Power = Energy/time)
4.
a.
b.
c.
This question is about fuses.
What is the function of a fuse in a circuit?
Draw the circuit symbol for a fuse.
To which wire in the plug should the fuse wire
be connected?
d. Should the wire used in a fuse have a high or
low melting point?
5. The 3-pin plug has three wires inside.
a. Name them and state the colour of
insulation of each.
b. Which wire is used as a safety measure to
prevent electric shock?
c. Which appliances do not require a 3-pin
plug?
6.
a.
b.
c.
Magnets have special properties.
Name two properties of a magnet.
State the law of the magnetic poles.
Name the instrument used to show the
direction of field lines.
d. State one way by which a permanent
magnet can be demagnetised.
7. A solenoid with a current passing through
it has a magnetic field around it.
a. Name the rule which is used to find the
North pole of the solenoid.
b. What pole will form at end A?
A
8. Magnetic fields can have different shapes.
Draw the magnetic field of a:
a. bar magnet
b. two like poles
c. two unlike poles.
9. A magnetic field forms around a current
carrying conductor.
a) Draw the resulting magnetic field
around the wire.
b) How can the magnetic field be made
stronger?
10. An electromagnet is temporary magnet
which is dependent on current. Name:
a. the material which is used to make an
electromagnet.
b. two ways by which it can be made
stronger.
11. Explain briefly how this relay works.
12. Draw the apparatus required to test how
the strength of an electromagnet depends
on the current. Label all the apparatus.
13. This question is about the catapult force.
a. The wire experiences the greatest force
when it is ___________ to the magnetic
field.
b. State the direction of the force in this case.
c.
State two ways by which the size of this
force can be increased.
14. A motor can be made to turn faster and a
loudspeaker can be louder if three
identical changes are made to each one of
them. Name these changes.
15.
a) When the magnet is moved towards the coil, the
_________ cuts field lines of the ____________ and so a
current is i____________ in the coil. This can be noticed
because the pointer of the ________________ deflects.
b) What is observed if the magnet is not moved? Explain.
c) Name 3 ways by which the current can be made stronger.