Moving Charges and Magnetism

A square loop of edge length 2 m carrying current of 2 A is placed with its edges parallel to the x-y axis. A magnetic field is passing through the x-y plane and expressed as B = B0(1 + 4x) k, where B0 = 5 T. The net magnetic force experienced by the loop is N.

A proton and a deuteron (q = +e, m = 2.0 u) having same kinetic energies enter a region of uniform magnetic field B, moving perpendicular to B. The ratio of the radius rd of deuteron path to the radius rp of the proton path is:

1. 1 : 2
2. 1 : 1
3. 2 : 1
4. 1 : 2

An electron with kinetic energy 5 eV enters a region of uniform magnetic field of 3 perpendicular to its direction. An electric field E is applied perpendicular to the direction of velocity and magnetic field. The value of E, so that electron moves along the same path, is N C-1. (Given, mass of electron = 9 10-31 kg, electric charge = 1.6 10-19 C)

A long straight wire of radius a carries a steady current I. The current is uniformly distributed across its cross section. The ratio of the magnetic field at a2 and 2a from axis of the wire is :

1. 4 : 1
2. 3 : 4
3. 1 : 1
4. 1 : 4

Match List I with List II Choose the correct answer from the options given below:

1. A-I, B-III, C-II, D-IV
2. A-IV, B-II, C-III, D-I
3. A-III, B-I, C-II, D-IV
4. A-IV, B-III, C-II, D-I

An element l = x i is placed at the origin and carries a large current I = 10 A. The magnetic field on the y-axis at a distance of 0.5 m from the element x of 1 cm length is: [figure]

1. 10 10-8 T
2. 8 10-8 T
3. 4 10-8 T
4. 12 10-8 T

Match List I with List II: Choose the correct answer from the options given below :

1. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
2. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
3. (A)-(IV), (B)-(I), (C)-(III), (D)-(II)
4. (A)-(I), (B)-(III), (C)-(II), (D)-(IV)

In the given figure an ammeter A consists of a 240 coil connected in parallel to a 10 shunt. The reading of the ammeter is mA. [figure]

A coil having 100 turns, area of 5 10-3 m2, carrying current of 1 mA is placed in uniform magnetic field of 0.20 T such a way that plane of coil is perpendicular to the magnetic field. The work done in turning the coil through 90 is .

In a co-axial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero :

1. inside the outer conductor
2. outside the cable
3. in between the two conductors
4. inside the inner conductor