Class 10 Magnetic effects of current - Practice Worksheet
One marks questions
Question 1
How can you show that the magnetic field produced by a given electric current in the wire decreases as the distance from the wire increases?
Answer
If we slowly take away a magnetic compass from a current carrying conductor,the deflection of the compass decreases. this clearly shows that magnetic field decreases as we increase the distance of the wire{current}
Question 2
What is the advantage of the third wire of earth connection in domestic appliances?
Answer
It prevents us from electric shock. Bsaically third wire of earth connection in domestic electrical application conducts charge that appears on the body of appliance into the earth. So saving the user from an electric shock.
Question 3
How is the strength of the magnetic field at a point near a wire related to the strength of the electric current flowing in the wire?
Answer
The strength of the magnetic field is directly propotional to the current flowing through the wire.
Question 4
On what effect of an electric current does an electromagnet work?
Overloading
If more electrical appliances of high power rating like electric iron box, electric cooker, electric heater, air conditioner etc., are switched on at the same time, they draw an extremely large current from the circuit is called overloading. Check Animation here
Short-circuiting
Sometimes, the live and neutral wires come in the direct contact due to defective or damaged wiring. When this happens, the resistance of the circuit becomes almost zero and a very large current flows through it. This is known as Short Circuit.
Question 6
Explain the function of earth wire. Why is it necessary to earth metallic appliances? Question 7
All household appliances are connected in parallel. List two advantages of this type of arrangement.
Answer
(i) To have equal potential difference across each appliance.
(ii) Each appliance has separate switch to the flow of current through it, so that each circuit can work independently
Question 8
What is a solenoid?
Answer
The solenoid is a long cylindrical coil of wire consisting of a large no. of turns bound together very tightly.When current is flown through solenoid,One end of the Solenoid behaves like North Pole and the other end behaves like the South Pole. Magnetic field lines inside the solenoid are in the form of parallel straight lines.
This means that the field is same at all the points inside the solenoid.
Question 9
What kind of magnetic field is produced by a current carrying solenoid?
Answer
The magnetic field due to a solenoid is very much similar to that of a bar magnet. The pattern of the magnetic field lines around a current-carrying solenoid is similar to that of bar magnet.Just like a bar magnet, one end of the solenoid behaves as a magnetic north pole, while the other behaves as the South Pole.
Question 10
Why does a compass needle show deflection when brought near a bar magnet?
Answer
The needle of a compass is a small magnet. That s why when a compass needle is brought near a bar magnet, its magnetic field lines interact with that of the bar magnet. Hence, a compass needle gets deflected.
Question 11
Why are magnetic field lines more crowded towards the pole of a magnet?
Answer
Strong force near the poles
Question 12
What are magnetic field lines? Question 13
Draw a diagram to represent a uniform magnetic field in a given region. Question 14
For same current flowing through a solenoid and a straight conductor, the magnetic field produced by a solenoid is much stronger than the magnetic field produced by a straight current carrying conductor. State one reason to justify this statement. Question 15
Why does a current carrying conductor experience a force when it is placed in a magnetic field?
Answer
The current carrying conductor generates it own magnetic field around it. This interracts with the external magnetic field. When two magnetic fields interact there will be attraction and repulsion between them based on the direction of the external magnetic field and the direction of the current in the conductor. That is reason the current caryying conductor experiences a force.
Question 16
How is the type of current that we receive in domestic circuit different from the one that runs in a clock?
Answer
We receive Alternating current in Domestic circuit while direct currents runs in a clock
Question 17
What type of current is given direct current? Question 18
What type of current is used in household supply?
Answer
Alternating current
Question 19
Why do we connect earth wire in a house? Give two reasons. Question 20
What is the difference between a direct current and an alternating current. How many times does AC used in India change direction in one second? Question 21
What is the role of fuse used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?
Long Answer Questions
Question 22
(a) A stationary charge is placed in a magnetic field. Will it experience force? Give reason and justify your answer.
(b) On what factors does the direction of force experienced by a current carrying conductor when placed in a magnetic field depends?
(c)Under what conditions is the force experienced by a current carrying conductor placed in a uniform magnetic field is maximum.
Answer
(a) No, a magnetic field exerts a force only on moving charges.
(b) The direction of force experienced by a current carrying conductor placed in a magnetic field depends on the direction of the current in the conductor and the direction of the applied magnetic field. This is given by Fleming's left hand rule.
(c) The force experienced by a current carrying conductor is maximum when the current and magnetic field are at right angles to each other.
Question 23
List four important features of domestic electric circuit. Draw a diagram of common domestic circuit showing live, neutral and earth wires. Question 24
What is an electromagnet?
(i) Draw a circuit diagram to show how a soft iron piece an be transformed into an electromagnet.
(ii)How can we determine north and south pole of an electromagnet with the help of magnetized iron bar?
Question 25
How will the magnetic field produced in a current carrying a circular coil change, if we increase the:
(i) Value of current flowing through it?
(ii) Distance of point P from the coil?
(iii) Number of turns of the coil?
Question 26
With the help of a diagram for experimental set up, describe an activity to demonstrate that the strength of a magnetic field at a point increases with increase in current in the straight conductor.
Question 27
How can we demonstrate the formation of magnetic field surrounding a magnet?
Question 28
Why do two magnetic field lines never intersect each other? Explain.
Question 29
Briefly explain an activity to plot the magnetic field lines produced round a straight current carrying conductor.
Question 30
How is the fuse connected in an electric circuit?
Question 31
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 at a point directly above it? Name the rule you have applied in this case.
Question 32
Compare the pattern of the field produced in case of a current carrying solenoid with the magnetic field of a bar magnet.
Deleted Syllabus Questions
Question 1
(a) Name two electrical appliances of daily use in which electric motor is used.
(b) Name and state the principle on which an electric motor works.
Question 2
In Faraday’s experiment if instead of moving the magnet towards the coil we move the coil towards the magnet, will there be any induced current? Justify your answer. Compare the two cases. Question 3
Explain briefly two different ways to induce current in a coil. State the rule which determines direction of induced current. Question 4
Whenever there is a relative motion between magnet and a coil, a current is induced in the coil. Name this phenomenon.
Answer
ElectroMagnetic Induction
Question 5
List in tabular form two major differences between electric motor and electric generator.
Question 6
With the help of a neat-diagram, describe how you can generate induced current in a circuit.
Question 7
State the principle of an electric generator. Question 7 What is the function of a split ring in an electric motor? Question 11 Draw a labelled diagram of an electric motor. Explain its principle and working. Question 8
A coil made of insulated copper wire is connected to a galvanometer. What will happen to the deflection of the galvanometer if bar magnet is pushed into the coil and then pulled out of it. Give reason for your answer and the phenomenon involved.
Answer
When bar magnet is pushed into the coil, a current will be induced in the coil. The current in the coil will let the galvanometer show a deflection.
When bar magnet is pulled out of coil it will again induce a current in the coil but this time the current will be induced opposite to the previous direction. The galvanometer will deflect in opposite direction.
When the bar magnet is pushed or pulled ,the magnetic field associated with the coil is changed And changing magnetic field leads to an induced current in the conductor. So current flows in the coil and deflection is shown in galvanometer
The phenomenon is known as electromagnetic induction.
Question 9
A coil of insulated wire is connected to a galvanometer. What would beseen if a bar magnet with its south pole towards one face of the coil is:
(a) Moved quickly towards it?
(b) Moved quickly away from it?
(c) Placed near its once face?
(d) Name the phenomena involved.
Answer
(a) Deflection in galvanometer
(b) Deflection in galvanometer
(c) No deflection in galvanometer
(d) Electromagnetic Induction
Question 10
(i)Two circular coils A and B are placed close to each other. If the current in the coil A is changed, will some current be induced in coil B? Give reason.
(ii)With the help of diagram describe an experiment to show that a change in current flowing through a coil induces an electric current in a neighbouring coil. Download this as pdf
