Radiation of wavelength 180 nm ejects photoelectrons from a plate whose work funcion is 2.0 eV. If uniform magnetic field of flux density `5.0 xx 10^-5 T` is applied parallel to the plate, what should be the radius of the path followed by electrons ejected normally from the plate with maximum energy.

A magnetic field of flux density 10 T acts normal to a coil of 50 turns having 100cm^2 area. Find e.m.f. iduced, if the coil is removed from the magnetic field on 0.1 s.

A beam of protons with a velocity of 4 xx 10 ^5 ms^(-1) enters a uniform magnetic field of 0.3 T. The velocity makes an angle of 60^@ with the magnetic field. Find the radius of the helicla path taken by the proton beam and the pitch of the helix. Given that mass of proton = 1.67 xx 10^-27kg

A small retangular coil ABCD contains 140 turns of wire. The sides AB and BC of the coil are of length 4.5 and 2.8 cm respectively, as shown in the figure The coil is held between the poles of a large magnet so that the coil can rotate about an axis thorugh its centre. The magnet produces a uniform magnetic field of flux density B between its poles. When the current in the coil is 170 mA, the maximum torque produced in the coil is 2.1 xx 10^-3 N m . For the coil in the position for maximum torque, state whether the plane of the coil is parallel to, or normal to , the direction of the magnetic field.

A monoenergtic electron beam with electron speed of 5.20 xx 10^6 ms^-1 is subjected to a magnetic field of 1.30 xx 10^-4 t normal to beam velocity. What is the radius of the circle traced by the beam, given e/m for electron equals 1.76 xx 10^11 kg^-1 ?

A small retangular coil ABCD contains 140 turns of wire. The sides AB and BC of the coil are of length 4.5 and 2.8 cm respectively, as shown in the figure The coil is held between the poles of a large magnet so that the coil can rotate about an axis thorugh its centre. The magnet produces a uniform magnetic field of flux density B between its poles. When the current in the coil is 170 mA, the maximum torque produced in the coil is 2.1 xx 10^-3 N m . The current in the coil in (a) is switched off and the coil s positioned as shown in the figure. The coil is then turned thorugh an angle of 90^@ in a time of 0.14 s. Calculate the average e.m.f. induced in the coil.

A bar magnet having a magnetic moment of 1.0 xx 10^4 J T^(-1) is free to rotate in a horizontal plane. A horizontal magnetic field B = 4 xx 10^(-5) T exists in the space. Find the work done in rotating the magnet slowly from a direction parallel to the field to a direction 60^@ from the field.

A short bar magnet placed with its axis at 30^@ with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 xx 10^-2 J .What is the magnitude of magnetic moment of the magnet?