A current i amp flows along an infinitely long straight conductor. If r metre is the perpendicular distance of a point from the lower end of the conductor, then the magnetic induction b is given by [ MPPMT 1994]

The velocity of helium nucleus traveling in the a current path in a magnetic field is v. The velocity of the proton moving along the same path in the same magnetic field field is [ CPMT 1993]

In the hydrogen atom, the electron revolves in circular orbit of radius 0.53×10-10 metre and makes 6.6×1015 r.p.s. Then the magnetic dipole moment is approximately [ MPPMT 1999]

Which of the following graph shows the variation of magnetic induction B with distance r from a long wire carrying current : [ MPPMT 1999]

A deuteron of kinetic energy 50 KeV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to magnetic field B. The kinetic energy of the proton that describe a circular orbit of radius 0.5 metre in the same plane with the same B is [ CBSE 1991]

A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be [ CBSE 1991]

A current loop is placed in a uniform magnetic field. The loop will experience [ CBSE 1993]

A particle of charge q and mass m moving with velocity v along the x-axis enters the region x > 0 with uniform magnetic field B along the k direction. The particle will penetrate in this region in the x-direction up to a distance d equal to [ MPPMT 1997]

A current of 1 amp is passed through a straight wire of length 2.0 metres. The magnetic field at a point in air at distance of 3 metres from either end of wire and lying on the axis of wire will be [ MPPMT 1995]

A wire of fixed length L can be formed into many circular loops of varying radii r depending on the number of turns n. The loop so formed is carrying a current and is so placed normally in a uniform magnetic field B. In order that the torque on the circular loop formed be maximum, the number of turns n must be equal

A proton and an alpha particle enter in a uniform magnetic field with same velocity. The period of rotation of the alpha particle will be [ mPPMT 1990]

An electron of charge e is going around in an orbit of radius R metres in hydrogen atom with velocity v m/s. The magnetic flux density associated with it at its centre is [ CBSE 1993]

H+, He++ and O++ all having same kinetic energy pass through a region in which there is a uniform magnetic filed perpendicular to their velocity. The masses of H+,He++ and O++ are 1 amu. 4 amu and 16 amu respectively. Then [ IIT 1994]

Weber ampere per meter is equal to [ MPPMT 1990]

An electron of mass 9×10-31 kg, charge 1.6 ×10-19 C moving with velocity 106 m/s enters a region of magnetic field of strength 5×10-5T perpendicular to the field. Find the radius of the circle described by it

A proton of mass 1.67×10-27 kg and charge 1.6×10-19 C is projected with a speed of 2×106 m/s at an angle of 60° to the x-axis. If a uniform magnetic field of 0.104 tesla is applied along the Y-axis, the path of the proton is [ IIT 1995]

A current is flowing in a circular loop of radius R and the magnetic field at its centre is Bo. At what distance from the centre on the axis of the coil, the magnetic field will be Bo / 8? [ MPPMT 1997]

Three long, straight and parallel wires carrying currents are arranged as shown in figure. the wire C which carries a current of 5.0 amp is so placed that it experiences no force. the distance of wire C from D is then [ AMU 1995]

A conductor in the form of right angle ABC, with AB=3 cm and BC=4 cm, carries a current of 10A. There is uniform magnetic field of 5T, perpendicular to the plane of the conductor. The force on the conductor AC will be [ MPPMT 1997]

Along vertical wire in which current is flowing produces a neutral point with the earth's magnetic field at distance of 5 cm's from the wire. If the horizontal component of the earth's magnetic induction is 0.18 gauss then current in the wire is

A very long solenoid has 800 turns per metre length of solenoid. A current of 1.6 ampere flows through it. Then the magnetic induction at the middle point of the solenoid on its axis, is approximately

P is a point at a distance a from a long, thin straight wire carrying current i as shown in figure. The magnetic field at P is

A long thick metallic cylinder of radius R has a current of i ampere uniformly distributed over its circular cross-section. then, magnetic induction B away from the axis at a distance r from the axis varies as shown in figures given in options

A cable carries a current of 1A vertically upward. The magnetic field produced by it at a point 10 cm north will be

Magnetic field at the centre of the cube of edge of length a is

A straight conductor of length 0.3 metre is placed in uniform magnetic field of induction 8 × 10-4 tesla, normal to the lines of the force. A current of 2.5 ampere flows through it. The mechanical force acting on the conductor, is

A circular wire is carrying a current in anticlockwise direction as shown in figure . A long infinite wire CD is placed above the plane of page and carries a current as shown. The force acting on wire CD is

A long wire carries a steady current. First it is bent into a circular coil of one turn when magnetic induction at the centre is B. Then the same wire is bent to form a circular coil of smaller radius but n turn when the magnetic induction at the centre is B', then

A rectangular coil of area A of N turns has a current I flowing in clockwise direction when looked at from above. The magnetic moment associated with it

Two concentric circular coils 1 and 2 have radii 20cm and 10cm respectively lie in the same plane. the current in coil 1 is 0.5A in anticlockwise direction. The current in coil 2, so that net field at the common centre is zero, is