# Class 10 Magnetic effects of current Extra Questions

## One marks questions

Question 1
If the current in a wire is flowing in the vertically downward direction and a magnetic field is applied from west to east, what is the direction of force on the wire?

By fleming left hand rule, the direction of force will be towards south

Question 2
When do we apply Flemings (i) Left hand (ii) Right hand rule.>

Flemings Left hand rule is used to find the force experience by the current carrying conductor in Magnetic Field
Flemings Right hand rule is used to find the direction of induced current of moving conductor in magnetic field

Question 3
How much force is exerted by a magnetic field on a stationary charge?

zero

Question 4
A positive charge is moving vertically upwards, when it enters a region of magnetic field directed toward north, what is the direction of force on the charge?

West

## Two marks questions

Question 5
Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.

When the current in coil A is changed, the magnetic field associated with it also changes. As a result, the magnetic field around coil B also changes. This change in magnetic field lines around coil B induces an electric current in it. This principle is called electromagnetic induction.

Question 6
(a) Why do we connect earth wire in a house? Give two reasons.
(b) What type of current is used in house hold supply and what type of current is given by a cell?

(a) Earth wire are used to prevent electric shock to us
(b) Alternating Current(AC) is used in house hold supply and Direct Current(DC) is given by cell

Question 7
To which wire do you connect fuse wire in a house hold circuit? Write name of one source of AC current and one source of DC current.

Fuse wire is connected to the Live wire.House hold supply is AC current and Electric cell provides DC current

Question 8
A magnetic compass shows a deflection when placed near a current – carrying wire. How will the deflection of the compass get affected if the current in the wire is increased? Support your answer with a reason.
Question 9
What is the full form of MRI?

Magnetic Resonance Imaging

Question 10
Why can’t two magnetic field lines cross (intersect) each other?

Magnetic Field lines cannot cross each other. If it happens that at point of intersection, the compass needle will point in two direction which is not possible

Question 11
State the rule for finding the direction of the magnetic field produced around a current carrying conductor.

Flemings Left Hand rule

Question 12
Mention the shape of the magnetic field lines around a current carrying straight conductor.

Co-centric Circles

Question 13
A current carrying conductor in a magnetic field experiences a force. Write the condition for this force to be maximum.

Force is maximum when current direction is perpendicular to Magnetic field direction

Question 14
Name and state the rule that helps to find the induced current in electromagnetic Induction.

Flemings Right hand rule

Question 15
An alternating electric current has a frequency of 50 Hz. How many times does it changes its direction in one second? Give reason for your answer.

50Hz means 50 cycle/sec. Now in one cycle, current changes direction twice, So 100 times per sec

## Three marks questions

Question 16
(a) Define the term current rating of an electric fuse?
(b) Name the material used to make electric fuse?
(c) Name two safety measure commonly used in electric circuit and appliances?

(a) Electric Fuse current rating defines the maximum value of safe current allowed to flow through fuse with out melting it
(b) Tin-lead alloy is general used to make fuse wire
(c) Electric Fuse and Earthing

Question 17
Compare the pattern of the magnetic field around a solenoid with the magnetic field around a bar magnet.
Question 18
A compass needle is placed near a current – carrying wire. State your observation for the following cases and give reason for the same in each case:
(i) Magnitude of electric current in the wires increased.
(ii) The compass needle is displaced away from the wire.
Question 19
Explain why electrical appliances are connected in parallel in household circuits.
Question 20
Draw the pattern of magnetic field lines of a solenoid through which a steady current flows.
Question 21
(i)What is the role of fuse, used in series with any electrical appliance? (ii)Why should a fuse with defined rating not be replaced by one with a larger rating?
Question 22
Draw an appropriate schematic diagram showing common domestic circuits and discuss the importance of fuse. Why is it that burnt out fuse should be replaced by another fuse of identical rating?

Question 23
(a)Write four properties (characteristics) of magnetic lines of forces.
(b) Give two uses of magnetic compass.

Question 24
(a) What is a solenoid? Draw the pattern of magnetic field lines around a current carrying solenoid.
(b) What is the pattern of field lines inside a solenoid? What do they indicate?
(c) How is the magnetic field produced in a solenoid used?
(d) How can this field be utilized to magnetise a piece of soft iron?

Question 25
You are given three identical looking bars one of which is a magnet, the other made of a magnetic material and the third made of the third made of a non – magnetic material. Using just three bars how will you find out which is which?

Question 26
An electric fuse of rating 3 A is connected in a circuit in which an electric iron of power 1.5 kilo watt is connected which operates at 20 V. What would happen? Explain.

Question 27
An electric oven is 1.5 kW is operated in a domestic circuit (220 V) that has a current rating of 5 A. What result do you expect in this case? Explain.

Question 28
Name the three factors on which the force on the current carrying conductor depend?

Table type question
A current carrying conductor is placed in Magnetic Field.
Current is I
Length is L
Magnetic Field in B
Force on the conductor is given by below formula
F=ILBsinθ
 Angle between current carrying conductor and Magnetic Field 0 90 30 60 Force on the conductor ? ? ? ?
Some more questions to be answered based on above data
1. At what angle, the force is maximum
2. At what angle, the force is minimum