Lakhmir Singh solutions for फिज़िक्स [इंग्रजी] इयत्ता १० आईसीएसई chapter 10 - Electromagnetism [Latest edition]

How do magnets attract or repel? Can they stick to all types of metals?

How can you find out the north and south poles of a magnet using another magnet with its north and south poles clearly labelled?

The core of an electromagnet must be made of soft iron. Why? What happens if soft iron is replaced with steel?

What is the use of a permanent magnet?

What will happen to a magnetic needle when it is brought close to a current-carrying conductor?

State the law which is used to find the direction of magnetic field lines.

Describe some experiment to show that the magnetic field is associated with an electric current. 

Name two factors on which the strength of magnetic field of an electromagnet depends ?

State the principle of a D. C. motor.

Name the device which is used to reverse the direction of current in the coil of a motor?

State the factors that can increase the speed of rotation of the coil in a D.C. motor.

Why is an electromagnet used in an electric bell?

State two differences between an electromagnet and a permanent magnet.

When is the force experienced by a current-carrying conductor placed in a magnetic field largest?

State whether the following statement is true or false.

Fleming's right-hand rule is used for finding the direction of a force in a DC motor.

State whether the following statement is true or false.

The denser is the magnetic field lines, the stronger is the magnetic field.

Which of the following is not part of the simple motor?

______ force experienced by a charge travelling in a magnetic field against the direction of the magnetic field.

A DC motor converts ______ energy to ______ energy.

If you hold a coil of wire next to a magnet, no current will flow in the coil. What else is needed to induce a current? 

Can a magnet with a single pole actually exist?

Why do we not use DC for power transmission? Is it possible to supply DC directly to homes in place of AC?

Can you think of a few applications of AC generators?

A portable radio has a built-in transformer so that it can work from the mains instead of batteries. Is this a step-up or step-down transformer?

On which factors the direction of induced emf depends?

How can we increase the maximum value of emf induced in an AC generator?

Define a Transformer.

Explain the construction and working of the transformer. 

How is an emf induced in an AC generator?

State five differences between an AC generator and a DC motor.

State Faraday’s laws of electromagnetic induction.

State whether the following statement is true or false.

In a step-down transformer, the number of turns in the primary coil is more than the number of turns in secondary coil.

State whether the following statement is true or false.

A transformer works on the principle of electromagnetic induction.

A step-up transformer is used in ______.

The frequency of alternating current (a.c.) supply in India is ______.

Lenz's law is used to find the direction of ______ in AC generators.

In ______ current, polarity reverses with time.

True or False.

An AC generator converts mechanical energy to electrical energy.

True or False:

Force on a current-carrying conductor depends upon the area of cross-section of the conductor.

True or False:

Electrical energy converts into mechanical energy when a magnet is moved towards a coil.