A long, straight wire of radius R carries a current distributed uniformly over its cross-section. The magnitude of the magnetic field is 

(a) maximum at the axis of the wire
(b) minimum at the axis of the wire
(c) maximum at the surface of the wire
(d) minimum at the surface of the wire. 

Choose the correct option 

1. (a), (b)

2. (b), (c)

3. (c), (d)

4. (a), (d)

A hollow tube is carrying an electric current along its length distributed uniformly over its surface. The magnetic field, 

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

(a) outside the cable
(b) inside the inner conductor
(c) inside the outer conductor
(d) in between the two conductors

Choose the correct option 

1. (a) only

2. (b), (c)

3. (c), (d)

4. (a), (d)

A steady electric current is flowing through a cylindrical conductor. 

(a) The electric field at the axis of the conductor is zero.
(b) The magnetic field at the axis of the conductor is zero.
(c) The electric field in the vicinity of the conductor is zero.
(d) The magnetic field in the vicinity of the conductor is zero

Choose the correct option 

1. (a), (b)

2. (b), (c)

3. (c), (d)

4. (a), (d)