Download Comms Revision Questions

Y11 REVISION Communications (PD5)
1) Explain how the train below is able to float and move using magnetism
2)
a) Name 2 ways that you can turn an iron nail into a magnet
b) Describe 3 ways that you can destroy a magnet
c) Describe two ways that you can show the magnetic field around a magnet
3)
a) Describe how to make an electromagnet from a nail, battery and wire
b) Why is an electromagnet used in car scrap yards?
c) give 6 uses for an electromagnet
4) Which way will the wire move in each of these "motors" (hint use Flemings hand rule)
A)
+
B)
N
-
-
S
C)
N
+
S
-
D)
S
N
+
E)
N
+
S
S
N
4) Using the diagram below explain how an Alternating current is produced from a generator
wooden block
magnet
B
wire
yoke
A
B
A
6)
a)What is the symbol shown below?
b) what does it do?
In Position 1 this is the amount
of current generated
i)
c) Describe what the component above does in the following 2 circuits
ii)
+
-
V
G
7)
a) A Transformer has 2000 turns on it’s primary coil. The voltage supplied to this coil is
240V. How many turns are on the secondary coil if the voltage on it is 48V?
b) Draw a diagram of what this transformer might look like.
c) What sort of Transformer is it?
d) Explain why it needs an AC voltage to work.
e) calculate the number of turns on the secondary coil of the following Transformers
30 Turns
10 Turns
i)
ii)
75v
15v
24v
96v
8) The leaning tower of Pisa is 45m high. A mass of 4kg is dropped from the top calculate
a) The Potential energy at the top of the tower
b) The Kinetic energy a fraction of a second before it hits the ground
c) The velocity a fraction of a second before it hits the ground
d) A ball bearing of mass 1kg is dropped from a height of 1m describe what happens to it's
potential and kinetic energy at the three points shown
Position 1
Position 2
1m
Position 3
0.5m
0.25m
Position 4
Ground