Download SA1 REVISION WORKSHEET 3

BUDS PUBLIC SCHOOL, DUBAI
PHYSICS WORKSHEET
TOPIC- Magnetic Effects Of Electric current
Name:________________________
Class:10
Sec:___
I Very Short Answer Type Questions
1. What is the frequency of an alternating current if its direction changes after
0.01S?
T=(0.01+0.01)=0.02s
F=1/T=1/0.02=50Hz.
2. How can it be shown that a magnetic field at a point near a wire related to
the strength of the electric current flowing in a wire?
Place a compass needle near to a current carrying conductor. If the
current through the conductor increased, the deflection of compass needle
also increased and vice versa.
3. Name the physical quantity whose SI unit is Wb-m2. I sit a scalar quantity or
vector quantity.
Magnetic flux.Vector quantity.
4. How will the Magnetic field intensity at the centre of a circular loop carrying
current change, if the current through the coil is doubled and the radius is reduced
into half?
5. What will happen when a current carrying conductor is placed in a perpendicular
magnetic field?
The forc experienced by the conductor will be maximum.
II Short Answer Type Questions
1. Differentiate between short circuiting an overloading of electric circuits.
How does a fuse wire protect an electric circuit?
Refer notes
2. What is the difference between direct and alternating currents? Write
advantage of using alternating current?
Refer notes
3. With the help of neat diagram describe how you can generate induced
current in a coil.
Refer activity13.8 or 13.9 and fig 13.16 or 13.17 resp. from textbook.
4. Draw the pattern of field lines due to solenoid carrying current. Mark north
and south pole in the diagram.
Refer page no:229, fig.13.10 in the text book.
5. A current carrying conductor experiences a force when it placed in a
magnetic field? Give two application of this? Under what conditions is this
force maximum?
Applications are
1) Electric motor
2)Loud speaker
The force is F=BIlsinθ
When the conductor is perpendicular to the magnetic field, the force will be
maximum.
6. What is an electromagnetic induction? Write the rule that is used to find the
direction of induced current.
Refer notes
7. Write the use of split rings, brushes, armature (coil with shaft) in a electric
generator.
Refer notes
8. A current through a horizontal power line flows in east to west direction. What
is the direction of magnetic field at a point directly below it and directly above it?
The current is in the east-west direction. Applying the right-hand thumb rule,
we get that the direction of magnetic field at a point below the wire is from north to
south. The direction of magnetic field at a point directly above the wire is from
south to north.
9. State the rule to determine the direction of a
(a) Magnetic field produced around a straight conductor carrying current.
Right-hand thumb rule: For statement refer notes.
(b) Force experience by a current carrying straight conductor placed in a magnetic
field which is perpendicular to it.
Fleming’s left-hand rule: For statement refer notes
c) Current induced in coil due to its rotation in magnetic field.
Fleming’s right hand rule-For statement refer notes.
III Long Answer Type Questions
1. (a) Draw a schematic diagram of a domestic electric circuit which includes a
main fuse, power meter, a distribution box and power plugs.
Refer notes-domestic electric circuits
(b) Why is it necessary to earth the metallic electric appliances?
Refer notes-domestic electric circuits
3 .(a) Draw a labelled diagram to show how an electromagnet is made.
An electromagnet consists of a long coil of insulated copper wire
wrapped on a soft iron core.
For fig ,Refer page no 229,fig.13.11 in the text book.
(b)What is the purpose of the soft iron core used in making an electromagnet?
The soft iron inside the coil makes the magnetic field stronger because it
becomes a magnet itself when the current is flowing. Soft iron is used because it
loses its magnetism as soon as the current stops flowing.
(c) Name the materials used to make permanent magnets.
Permanent magnets are made of carbon steel, chromium steel and some alloys like
Alnico and Nipermag. Alnico is an alloy of aluminium, nickel and cobalt.
Nipermag is an alloy of iron, nickel, aluminium and titanium.
(d)State any two uses of permanent magnets.
Permanent magnets are used in microphones, loudspeakers, electric clocks and many
measurement tools like speedometers, galvanometer, ammeter and voltmeter ,etc.
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