What is magnetic flux density? Define its units and give its dimensions.

2

(a)

What is the magnetic effect of current? Describe the nature of the magnetic field related with the current in circular coil.

2

(a)

A wire of length l metre carries a current I ampere along the Y-axis. A magnetic field, \(\overset { \rightarrow }{ B } ={ B }_{ o }\left( \hat { i } +\hat { j } +\hat { k } \right) \)tesla exists in space. Find the magnitude of the force on the wire.

2

(a)

What is an ammeter? How is it used in an electric circuit? How it differ from a voltmeter?

2

(a)

Identify the materials, which can be classified as paramagnetic and diamagnetic : Al, Bi, Cu, Na. 

2

(a)

Which material is used to make electromagnets and why ?

2

(a)

A rectangular coil of area \(2\times 10^{ -4 }m^{ 2 }\) and 40 turns is pivoted about one of its vertical sides. The coil is in a radial horizontal field of 60 G. What is the torsional constant of the hair springs connected to the coil, if a current of 4.0 mA produces an angular deflection of 16^o?

2

(a)

How does a circular loop carrying current behave as a magnet?

2

(a)

The horizontal component of the earth's magnetic field at a place is \(\sqrt { 3 } \)  times its vertical component here. Find the value of the angle of dip at that place. What is the ratio of the horizontal component to the total magnetic field of the earth at that place?

2

(a)

A square coil of side 10 cm consists of 20 turns and carries a current of 12 A. The coil is suspended vertically and the normal to the plane of the coil makes an angle of 30º with the direction of a uniform horizontal magnetic field of magnitude 0.80 T. What is the magnitude of torque experienced by the coil?

2

(a)

Give two points to distinguish between a paramagnetic and a diamagnetic substance.

2

(a)

Draw the magnetic field lines due to a current passing through a long solenoid. Use Ampere's circuital law, to obtain the expression for the magnetic field due to the current I in a long solenoid having n number of turns per unit length.

2

(a)

(i) Two long straight parallel conductors a and b carrying steady currents I_a and I_b respectively, are separated by a distance d. What is the nature and magnitude of the force between the two conductors?
(ii) Show with the help of a diagram, how the force between the two conductors would change when the currents in them flow in the opposite directions.

2

(a)

A charge particle moving in a magnetic field penetrates a layer of lead and thereby losses half of its kinetic energy. How does the radius of curvature of its path change?

2

(a)

You are given a copper wire carrying current I of length L. Now the wire is turned into circular coil. Find the number of turns in the coil so that the torque at the centre of the coil is to maximum

2

(a)