The magnetic field inside a long straight solenoid-carrying current

1

(a)

is zero

(b)

decrease as we move towards its end

(c)

increases a swe move towards its end

(d)

is the same at all points.

Which of the following property of a proton can change while it moves freely in a magnetic field ?

1

(a)

mass

(b)

speed

(c)

velocity

(d)

momentum

The strength of magnetic field inside a long current carrying straight solenoid is 

1

(a)

More at the ends than at the centre

(b)

Minimum in the middle

(c)

Same at all points

(d)

Found to increase from one end to the other.

To convert an AC generator into DC generator

1

(a)

Split-ring type commutator must be used

(b)

Slip rings and brushes must be used 

(c)

A stronger magnetic field has to be used

(d)

A rectangular wire has to be used.

The most important safety method used for protecting home appliances from short circuiting or overloading is

1

(a)

Earthing

(b)

Use of fuse

(c)

Use of stabilisers

(d)

Use of electric meter.

What is electric generator?

1

(a)

It is a device that converts mechanical energy into electrical energy.

What does an electric current carrying wire behaves like?

1

(a)

It behaves like a magnet.

Write any two differences between AC and DC.

1

(a)

DC	AC
1. Unidirectional flow of current.	Current changes its direction in a cycle.
2. Cells and batteries produce DC.	Dynamo produces AC.

 

Name the device that converts electric energy into mechanical energy.

1

(a)

An electric motor.

What kind of quantity is magnetic field?

1

(a)

It is a vector quantity as it has both magnitude and direction.