Magnetic Field Physics - Magnetic Field

A circular loop of area 1cm², carrying a current of 10A, is placed in a magnetic field of 0.1T perpendicular to the plane of the loop. The torque on the loop due to the magnetic field is:

1. Zero
2. 10⁴N-m
3. 10²N-m
4. 1N-m

A charged particle is whirled in a horizontal circle on a frictionless table by attaching it to a string fixed at one point. If a magnetic field is switched on in the vertical direction the tension in the string.

1. Will increase.
2. Will decrease.
3. Will remain the same.
4. May increase or decrease.

A beam consisting of protons and electrons moving at the same speed goes through a thin region in which there is a magnetic field perpendicular to the beam. The protons and the electrons:

1. Will go undeviated.
2. Will be deviated by the same angle and will not separate.
3. Will be deviated by different angles and hence separate.
4. Will be deviated by the same angle but will separate.

Which of the following particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field?

1. Electron
2. Proton
3. He⁺
4. Li⁺

The free electrons in a conducting wire are in constant thermal motion. If such a wire, carrying no current, is placed in a magnetic field, is there a magnetic force on each free electron? On the wire?

Can a charged particle be accelerated by a magnetic field? Can its speed be increased?

Suppose a charged particle moves with a velocity v near a wire carrying an electric current. A magnetic force, therefore, acts on it. If the same particle is seen from a frame moving with velocity v in the same direction, the charge will be found at rest. Will the magnetic force become zero in this frame? Will the magnetic field become zero in this frame?

Will a current loop placed in a magnetic field always experience a zero force?

Is it possible for a current loop to stay without rotating in a uniform magnetic field? If yes, what should be the orientation of the loop?

A rigid wire consists of a semi-circular portion of radius R and two straight sections The wire is partially immersed in a perpendicular magnetic field B, as shown in the figure. Find the magnetic force on the wire if it carries a current i.

An electron beam projected along the positive X-axis deflects along the positive Y-axis. If this deflection is caused by a magnetic field, what is the direction of the field? Can we conclude that the field is parallel to the Z-axis?

The net charge in a current-carrying wire is zero. Then, why does a magnetic field exert a force on it?

Assume that the magnetic field is uniform in a cubical region and is zero outside. Can you project a charged particle from outside into the field so that the particle describes a complete circle in the field?

A proton is projected with a velocity of 3 × 10⁶ ms^-1 perpendicular to a uniform magnetic field of 0.6T. Find the acceleration of the proton.

A current loop of arbitrary shape lies in a uniform magnetic field B. Show that the net magnetic force acting on the loop is zero.

A proton describes a circle of radius 1cm in a magnetic field of strength 0.10T. What would be the radius of the circle described by an α-particle moving with the same speed in the same magnetic field?

A current of 5.0A exists in the circuit shown in the figure. The wire PQ has a length of 50cm and the magnetic field in which it is immersed has a magnitude of 0.20T. Find the magnetic force acting on the wire PQ.

Shows a rod PQ of length 20.0cm and mass 200g suspended through a fixed point O by two threads of lengths 20.0cm each. A magnetic field of strength 0.500T exists in the vicinity of the wire PQ, as shown in the figure. The wires connecting PQ with the battery are loose and exert no force on PQ.

1. Find the tension in the threads when the switch S is open.
2. A current of 2.0A is established when the switch S is closed. Find the tension in the threads now.

A proton projected in a magnetic field of 0.020T travels along a helical path of radius 5.0cm and pitch 20cm. Find the components of the velocity of the proton along and perpendicular to the magnetic field. Take the mass of the proton = 1.6 × 10^-27kg

Suppose that the radius of cross-section of the wire used in the previous problem is r. Find the increase in the radius of the loop if the magnetic field is switched off. Young's modulus of the material of the wire is Y.