Conceptual questions on magnetic effects of current for Class 10 physics

Question 1) 

Arun while studying the force experienced by a current carrying conductor in a magnetic Field records the following observation


The force experienced by the conductor is increases as the current in the conductor is decreased


The force experienced by the conductor is decreases as the strength of magnetic field  is decreased


Direction of the force on the current carrying conductor is determined suing Fleming Left hand rule

Which of these observations is correct? Explain

Solution)   F=iLB

a) So as current is decreased, Force also decreases. Observation is Incorrect

b) Again, Force experience is decreased as strength of magnetic field is decreased. Observation is correct

c) Observation is correct

Question 2)

Write down the difference between permanent magnet and Electromagnet?


Permanent Magnet



Those magnets which have permanent magnetic field around it are called permanent Magnet

When a soft core is placed inside a solenoid and current is passed through it, the soft iron gets magnetized. The magnet so formed are called electromagnet


Permanent magnets are important for their industrial uses especially when it comes to power generation and electric motors. The induction process for turbines and generators needs permanent magnets to turn mechanical motion into energy. They are also important for electric motors in many electronics using the reverse of the induction of electric current to make mechanical energy. As you can see without the permanent magnet we would not be able to take full advantage of the capabilities of electricity in modern devices.

As soon as the current is stopped, the soft iron becomes demagnetized.

They are used in cranes, electric bell etc.

Question 3

 Why two magnetic field lines cannot intersect with each other?


if two magnetic field lines intersect with each other, then there will be two tangents drawn  which gives direction of magnetic field at the point of intersection. This is not possible

Question 4)

 A coil of insulated copper wire is connected to a galvanometer. What happens if a bar magnet is  


Pushed into the coil


Withdrawn from inside the coil


Held stationary inside the coil

What is the name of the phenomenon?



Pushed into the coil

An induced current is produced due to electromagnetic induction. Galvanometer will show deflection


Withdrawn from inside the coil

An induced current is produced due to electromagnetic induction. Galvanometer will show deflection in opposite direction


Held stationary inside the coil

No deflection

Phenomenon is electromagnetic Induction

Question 5) 

Answer these short questions regarding Magnetic field?

a) What does crowding of magnetic lines indicate?

b) SI unit of Magnetic field?

c) What is the direction of magnetic field lines outside a bar magnet?





What does crowding of magnetic lines indicate?

Strength of Magnetic field


SI unit of Magnetic field?



What is the direction of magnetic field lines outside a bar magnet?

North Pole to South Pole

Question 6

 What is difference between Direct Current DC and Alternating Current?

Which one is used to transmit long power over long distances?

What is the frequency of the Power transmission in India?


a) The difference are noted down below

Direct Current

Alternating current


Magnitude of current remains constant.

It flows in one direction in the circuit.

It changes continuously

It reverses its direction while flowing in a circuit




Battery provides direct current

AC  generator provides AC current


The frequency of alternating current is 50Hz or 60Hz depending upon the country.

The frequency of direct current is zero.

b) AC is used to transmit long power as loss of energy in transmission is comparatively small

c) 50Hz is the frequency of transmission of current in India

Question 7)

 Why do we use fuse in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with larger rating?


 Fuse is used for protecting appliances due to short circuit or overloading. The fuse is rated for a certain maximum current and blows off when a current more than rated value flows through it

If a fuse is replaced by one with large ratings, the appliances may get damaged while the protecting fuse does not burn off.

Question 8)

 True and False Statements

A) North poles repel North poles

B) South poles repel south poles

C) North poles attract south poles

D) South poles attract north poles

E) The force of attraction or repulsion varies directly proportional with the distance squared

F) The strength of a magnet varies at different locations on the magnet

G) Magnets are Weakest at their poles

H) The horse-shoe shape is very commonly used in magnetic separators because its lines of force are mostly at the open end of the horse-shoe, and this helps in the separation of ferrous materials. 

I) Magnetic field lines are closed loops.  They enter a magnet at its South Pole, and exit a magnet at its North Pole. 


A) True

B) True

C) True

D) True

E) False, it is inversely proportional

F) True

G) False, Magnets are strongest at the Poles

H) True

I) True

Question 9) 

Write Difference between Electric and Magnetic Field


Electric Field

Magnetic Field

It is created around electric charge

It is created around moving electric charge and magnets

The unit of electric Field is Newton per coulomb, ,volts per meter

The unit of magnetic Field is Gauss or Tesla

Force in Electric field is proportional to the electric charge

Force in magnetic Field is proportional to charge and speed of electric charge

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