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# Class 10 FRANK Solutions Physics Chapter 4.3 - Magnetic Effect of Current and Electromagnetic Induction

When do you use Fleming’s right-hand rule? Can you produce electricity with the help of magnetism? Find out by revising with our Frank Solutions for ICSE Class 10 Physics Chapter 4.3 Magnetic Effect of Current and Electromagnetic Induction. Also, brush up your understanding of direct current and alternating current.

At TopperLearning, you can study the science of electromagnetic induction with our ICSE Class 10 Physics Selina Solutions, concept videos and revision notes. In addition, you can test your Physics skills with our mock exam question papers and practice tests.

## Magnetic Effect of Current and Electromagnetic Induction Exercise 205

### Solution 1

Yes, we can produce electricity from magnetism.

### Solution 2

The production of electric current by moving a straight conductor in a magnetic field is called electromagnetic induction.

### Solution 3

Fleming's right hand rule can be stated as: Stretch the forefinger, the middle finger and the thumb of the right hand, such that they are mutually perpendicular to each other. If the forefinger indicates the direction of the magnetic field, thumb indicates the direction of motion of conductor, then the middle finger indicates the direction of induced current in the conductor.

### Solution 4

(i)
When the north-pole is pushed into the coil, a momentary deflection is observed in the galvanometer that indicates the production of a momentary current in the coil.
(ii)
When the magnet is held at rest, there is no deflection in the galvanometer, indicating that no current is produced in the coil.
(iii)
When the north-pole is pulled out from the coil, the deflection of the galvanometer is along the opposite direction, indicating the production of an opposite current.

### Solution 5

(i) Fleming's left hand rule is used to find out the direction of Lorentz force on a conductor. (ii) Fleming's right hand rule is used to find out the direction of induced current in a conductor.

### Solution 6

No, we cannot find out the magnitude of current using Fleming's right hand rule; we can find only the direction of induced current.

## Magnetic Effect of Current and Electromagnetic Induction Exercise 206

### Solution 7

If the current flows along the same direction with time, it is called a direct current (D.C.).

### Solution 8

If the current changes direction after equal intervals of time, it is known as alternating current (A.C.).

### Solution 9

Frequency of D.C. is zero.

### Solution 10

Frequency of A.C. used in India is 50 Hz.

### Solution 11

An alternating changes its direction after equal intervals of time but direct current does not change its direction.

### Solution 12

A generator with commutator (D.C. generator) produces D.C. current.

### Solution 13

A dynamo converts mechanical energy into electrical energy.

### Solution 14

A fuse is always connected in series, in household circuits.

### Solution 15

Three colours are:
(i) Red (for live wire)
(ii) Green (for earth wire)
(iii) Black (for neutral wire)

### Solution 16

Short circuiting occurs when the live wire comes in direct contact with the neutral wire so a zero resistance path is provided to the current. The heavy current then passes through the appliance and wires of the circuit.

### Solution 17

Precautions while using electricity:
(i) One must use wires or cables of current carrying capacity higher than the current which can flow through the circuit while using all appliances.
(ii) An electrical appliance must never be operated (or touched) with wet hands.

### Solution 18

Earthing is a safety device which is used to prevent shocks due to short-circuiting and leakages. Earthing, means that the metal body of an appliance, or the kWh meter of the house, is connected to a thick copper wire which is buried deep in the earth and at its end ia a copper plate surrounded by a mixture of charcoal and common salt. This prevents the users from getting shocks.

### Solution 19

An electric fuse is a device which is used to limit the current in an electric circuit. The use of a fuse thus safeguards the circuit and appliances connected in that circuit from being damaged. It is a short piece of wire made of an alloy of lead and tin. If the current passing through the fuse exceeds the safeguard limit the heat produced melts the fuse and this breaks the circuit.

### Solution 20

Colour code for live wire is red, neutral wire is black and earth wire is green.

### Solution 21

This is done to protect the appliances and circuits from any damage due to short-circuit and thus accidents like fire and fatal shocks. Earthing provides an easy and safe path to the excess current in the circuit and sends it to the ground.

### Solution 22

Switches are always connected in live wire.

### Solution 23

Fleming's right hand rule can be stated as: Stretch the forefinger, the middle finger and the thumb of the right hand, such that they are mutually perpendicular to each other. If the forefinger indicates the direction of the magnetic field, thumb indicates the direction of motion of conductor, then the middle finger indicates the direction of induced current in the conductor.

### Solution 24

Fleming's left hand rule can be stated as: Stretch the forefinger, the middle finger and the thumb of the right hand, such that they are mutually perpendicular to each other. If the forefinger indicates the direction of the magnetic field, the middle finger indicates the direction of current in the conductor then thumb indicates the direction of force exerted on the conductor.

### Solution 25

If a conducting wire is wound in form of a cylindrical coil whose diameter is less in comparison to the length, the coil is called a solenoid.

### Solution 26

No, a copper wire cannot be used as a fuse wire as it has low resistance and high melting point.

### Solution 27

A.C. is supplied to us in houses.

### Solution 28

An alloy of lead and tin is used for making fuse wire.

### Solution 29

Earthing is a safety device which is used to prevent shocks due to short-circuiting and leakages. Earthing, means that the metal body of an appliance, or the kWh meter of the house, is connected to a thick copper wire which is buried deep in the earth and at its end ia a copper plate surrounded by a mixture of charcoal and common salt. This prevents the users from getting shocks.

### Solution 30

Arrangement (a) is a series circuit.
Arrangement (b) is a parallel circuit.
We would prefer a parallel circuit in household because:
(i) In parallel arrangement, each appliance works at the same voltage.
(ii) In parallel arrangement, if one bulb (or appliance0 is switched off (or fuses), the other bulbs (or appliances) continue to glow (or operate).

### Solution 31

E is for earth pin, N is for neutral pin and L is for live pin.
The earth pin is long so that the earth connection is made first. This ensures the safety of the user because if the appliance is defective, the fuse will blow off. The earth pin is made thicker so that even by mistake it cannot be inserted into the hole for the live or neutral connection of the socket.
The pins are splitted at the ends to provide spring action so that they fit in the socket holes tightly.

### Solution 32

(i) The purpose of the terminal E is to provide earth connection.
(ii) Terminal E is connected to the earth pin of the plug.
(iii) Fuse is connected in series with the wire L, so that if excess current flows through the circuit, the fuse wire get heated up and melts thus, breaking the circuit and preventing the flow of current to the appliance.