MG SCHOOL EDUCATION: Cls 10 Sci Chp 13 prevs yr qn ans

Class 10 Science

Previous Years Appeared Questions and Answer

Chapter 13 Magnetic Effects of Electric Current

Multiple Choice Questions

1. The device used to produce electricity is (April - 2022)

(A) Galvanometer

(B) Electric generator

(D) Electric motor.

Ans: (B) Electric generator

2. In Fleming’s right hand rule, the middle finger indicates the direction of (April - 2022)

(A) induced electric current

(B) magnetic field

(D) mechanical force.

Ans. : (A) induced electric current

3. Observe the diagram.

The magnetic poles represented by P and Q respectively are (Sep - 2020)

(A) south ( ) and south (S)

(B) north ( N ) and south ( S )

(D) south (S) and north (N)

Ans. : (A) south (S) and south (S)

4. A device that converts electrical energy into mechanical energy is (June 2023)

(A) Electric generator (B) Electric motor

Ans. : (B) Electric motor

5. Imagine, you are holding a straight current carrying conductor as per the right hand thumb rule. If the thumb is upward, then the direction of the field lines of the magnetic field is (June 2023)

(A) downward (B) upward

Ans. :

One Mark Questions

1. What are the reasons for occurring overload in an electric circuit ? (June - 2022)

Ans:

★ Accidental hike in the supply voltage.

★ Connecting too many appliances to a single socket.

★ When live wire and neutral wire come into direct contact. ( Any two )

2. Magnetic field lines do not intersect each other. Why ? (April - 2022)

Ans. :

At the point of intersection the compass needle would point towards two directions which is not possible.

3. Suggest any two measures to avoid overloading in domestic circuits. (Sep - 2020)

Ans. :

★ Live and neutral wires should not come into direct contact.

★ There should not be any short-circuit in the circuit.

★ Too many appliances should not be connected to a single socket.

★ Should always use quality wires and good quality electrical appliances. (Any Two)

4. Observe the given figure.

What type of current is induced in the coil by doing the experiment related to this figure ? Give reason for your answer. (June - 2020)

Ans. :

★ Alternating current

★ Because the deflections in the galvanometer would just be opposite to the previous.

( Or galvanometer deflections are in opposite directions )

5. Observe the figure and mention the direction of the force acting on the current carrying conductor AB. Name the rule that helped you to find the direction of the force. (June 2023)

Ans. :

★ Towards left

Towards the magnet ( Or towards north pole of

the magnet )

★ Fleming’s left hand rule

6. What does the thumb indicate in the right hand thumb rule? (April 2023)

Ans. :

Direction of current

Two Marks Questions

1. Draw the diagram of a simple electric motor and label ‘Split rings’ ? (June - 2022) (June - 2020)

Ans:

2. Explain how overloading occurs in domestic electric circuit ? (June - 2020)

Ans. :

★ Over loading can occur when the live wire and the neutral wire come into direct contact

★ It can also occur due to an accidental hike in the supply voltage.

★ Sometimes overloading is caused by connecting too many appliances to a single socket. (Any two)

3. In domestic wiring electrical appliances are not connected in series. Why ? (June - 2020)

Ans. :

★In series arrangement if one appliance fails to work, then the circuit is broken and remaining appliances do not work.

★ The appliances in series draw same current in the circuit and hence do not operate properly.

Three Marks Questions

1. List the properties of the magnetic field due to the flow of electric current in a solenoid. What are the two methods of increasing magnetic field in a solenoid ? (June - 2022)

Ans. :

★ The magnetic field in a current carrying solenoid is similar to that of magnetic field produced in a bar magnet.

★ The magnetic field is uniform inside the solenoid.

The two methods to increase magnetic field in a solenoid.

¡) By increasing the number of turns of the coil.

¡¡) By increasing the current flowing through solenoid.

2. What are the functions of an earth wire ? It is necessary to connect the electric appliances having metallic body to earth wire in domestic electric circuit. Why ? Explain. (April - 2022)

Ans. :

Functions of the earth wire :

★ This is used as a safety measure for appliances have metallic body in domestic circuit

★This provides a low resistance conducting path for the current

★Any leakage of current in the appliances keeps its potential to that of the earth and the user may not get a severe electric shock.

3. Explain Faraday’s experiment related to electromagnetic induction. Mention the difference between direct and alternate current. (April - 2022)

Ans:

★ Take a coil of copper wire having a large number of turns connect the ends of the coil to a galvanometer

★ Take a strong magnet and move its one pole into the coil

★ There is a deflection in the needle of the galvanometer. This indicates the presence of a current in the coil

★Likewise, when the magnet is withdrawn back then also the needle of galvanometer deflects and this indicates the presence of electric current.

4. Observe the given diagram :

Explain the experiment related to this diagram. What conclusions can be drawn from this experiment? (June 2023)

Ans. :

★ Take two different coils of copper wire say 100 and 50 turns respectively. Insert them over a non-conducting cylindrical roll.

★ Connect the Coil-1 in series with a battery and plug key, Coil-2 with galvanometer

★ When the key is plugged in, needle of the galvanometer deflects and returns to zero. This indicates the presence of current in the Coil-2

★ Disconnect Coil-1 from battery. Needle of the

galvanometer deflects in the opposite direction and returns to zero. This indicates the opposite direction of the current.

Conclusions :

★ Changing electric current in Coil-1 induces current in Coil-2. This is electromagnetic induction.

★ This is due to the change in the magnetic field.

Four Marks Questions

1. Observe the given diagram. Explain the experiment related to this diagram. What conclusions can be drawn from this experiment ? (Sep - 2020)

Ans:

★ The ends of the copper coil ( AB ) are connected to a galvanometer. The north pole of the bar magnet ( NS ) is moved inside the coil. Induced current is produced in the coil and hence the needle of the galvanometer shows momentary deflection in one direction.

★ When the north pole of the magnet is withdrawn from the coil, the needle of the galvanometer is deflected in the opposite direction.

★ When the magnet is held stationary inside the coil, the deflection of the galvanometer drops to zero ( shows no deflection ).

★ When the magnet is moved inside the coil with greater force, galvanometer shows greater deflection and when the magnet is moved with smaller force, the galvanometer shows smaller deflection. When the magnet is stationary and the coil is moved towards / away from the magnet, galvanometer show deflection.

Conclusions that can be drawn from this experiment :

★ Motion of the magnet with respect to the coil produces an induced potential difference, which sets up an induced electric current in the circuit.

★ The direction of the induced current depends on the direction of the movement of the magnet inside the coil.

★ The amount of induced current is directly proportional to the force with which the magnet is moved into or withdrawn from the coil.

2. How do you trace the magnetic field lines around a bar magnet using compass needle ? Explain. Write the properties of magnetic field lines. (June - 2020)

Ans. :

★ Take a small compass and a bar magnet. Place a magnet on a sheet of white paper fixed on a drawing board. Mark the boundary of the magnet.

★ Place the compass near the north pole of the magnet mark the position of two ends of the needle.

★ Now move the needle to a new position such that the south pole occupies the position previously occupied by its north pole.

★ In this way proceed step by step till we reach the south pole of the magnet. Join the points marked on the paper by a smooth curve. This represents field line.

★ Repeating above procedure we can draw as many lines as possible.

Properties of magnetic field lines :

★ Field lines emerge from north pole and merge at the south pole.

★ At the poles field lines are crowded.

★ No two field lines are found to cross each other.

3. a) What is solenoid? Write the properties of the magnetic field lines formed around a current carrying solenoid.

b) What is alternating current? Electric appliances having metallic body are connected to earth wire, why? (June 2023)

Ans. :

★ A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid.

★ At the ends/poles of a solenoid, the magnetic fieldnlines appear in the form of concentric circles.

★ At the centre / inside the solenoid the magnetic field lines appear in the form of parallel straight lines.

★The current that changes direction after equal

intervals of time is called an alternating current.

★ The metallic body is connected to the earth wire provides a low resistance conducting path for the current.

★ Thus, it ensures that any leakage of current to the metallic body of the appliance keeps its potential to that of the earth and the user may not get a severe electric shock.