Magnetic Field due to a Current Physics - Magnetic Field due to a Current

A moving charge produces:

1. Electric field only.
2. Magnetic field only.
3. Both of them.
4. None of them.

A particle is projected in a plane perpendicular to a uniform magnetic field. The area bounded by the path described by the particle is proportional to:

1. The velocity.
2. The momentum.
3. The kinetic energy.
4. None of these.

A vertical wire carries a current in upward direction. An electron beam sent horizontally towards the wire will be deflected:

1. Towards right.
2. Towards left.
3. Upwards.
4. Downwards.

A circular loop is kept in that vertical plane which contains the north-south direction. It carries a current that is towards north at the topmost point. Let A be a point on the axis of the circle to the east of it and B a point on this axis to the west of it. The magnetic field due to the loop

1. Is towards east at A and towards west at B.
2. Is towards west at A and towards east at B.
3. Is towards east at both A and B.
4. Is towards west at both A and B.

A long, straight wire carries a current along the z-axis, One can find two points in the x−yplane such that:

1. The magnetic fields are equal.
2. The directions of the magnetic fields are the same.
3. The magnitudes of the magnetic fields are equal.
4. The field at one point is opposite to that at the other point.

Two proton beams going in the same direction repel each other whereas two wires carrying currents in the same direction attract each other. Explain.

Consider the situation described in the previous problem. Suppose the current i enters the loop at the point A and leaves it at the point B. Find the magnetic field at the centre of the loop.

A long solenoid is fabricated by closely winding a wire of radius 0.5mm over a cylindrical nonmagnetic frame so that the successive turns nearly touch each other. What would be the magnetic field B at the centre of the solenoid if it carries a current of 5A?

A circular loop of radius 4.0cm is placed in a horizontal plane and carries an electric current of 5.0A in the clockwise direction as seen from above. Find the magnetic field:

1. At a point 3.0cm above the centre of the loop.
2. At a point 3.0cm below the centre of the loop.

In order to have a current in a long wire, it should be connected to a battery or some such device. Can we obtain the magnetic due to a straight, long wire by using Ampere's law without mentioning this other part of the circuit?

You are facing a circular wire carrying an electric current. The current is clockwise as seen by you. Is the field at the centre coming towards you or going away from you?

A conducting circular loop of radius a is connected to two Iong, straight wires. The straight wires carry current I as shown in figure. Find the magnetic field B at the centre of the loop.

A tightly-wound, long solenoid has n turns per unit length, a radius r and carries a current i. A particle having charge q and mass m is projected from a point on the axis in a direction perpendicular to the axis. What can be the maximum speed for which the particle does not strike the solenoid ?

A long, vertical wire carrying a current of 10A in the upward direction is placed in a region where a horizontal magnetic field of magnitude 2·0 × 10^-3T exists from south to north. Find the point where the resultant magnetic field is zero.

The magnetic field B inside a long solenoid, carrying a current of 5.00A, is 3.14 × 10^-2T. Find the number of turns per unit length of the solenoid.

A circular loop of radius r carries a current i. How should a long, straight wire carrying a current 4i be placed in the plane of the circle so that the magnetic field at the centre becomes zero?

A long, straight wire carries a current. Is Ampere's law valid for a loop that does not enclose the wire? That encloses the wire but is not circular?

A current-carrying circular coil of 100 turns and radius 5.0cm produces a magnetic field of 6.0 × 10^-5T at its centre. Find the value of the current.

A solid wire of radius 10cm carries a current 5.0A distributed uniformly over its cross-section. Find the magnetic field B at a point at a distance (a) 2cm (b) 10cm and (c) 20cm away from the axis. Sketch a graph of B versus x for 0 < x < 20cm.

A copper wire having resistance 0.01 ohm in each metre is used to wind a 400-turn solenoid of radius 1.0cm and length 20cm. Find the emf of a battery which when connected the solenoid will eauee a magnetic field of 1.0 × 10^-2T near the centre of the solenoid.

Two parallel wires seprated by a distance of 10cm carry currents of 10A and 40A along-the same direction. Where should a third current be placed so that it experiences no magnetic force?

A wire of length l is bent in the form of an equilateral triangle and carries an electric currrent i.

1. Find the magnetic field B at the centre.
2. If the wire is bent in the form of a square, what would be the value of B at the centre?