A magnetic field of 2 x 10-2 T acts at right angles to a coil of area 100 cm2 with 50 turns. The average e.m.f. induced in the coil is 0.1 V when it is removed from the field in t sec. The value of t is
0.1 s
10 s
0.01 s
1s
Tesla is the unit of
magnetic flux
magnetic field
magnetic induction
magnetic moment
Two equal electric currents are flowing perpendicular to each other as shown in the figure. AB and CD are perpendicular to each other and symmetrically placed with respect to the currents, where do we expect the resultant magnetic field to be zero?
On AB
On CD
On both AB and CD
On both OD and BO
A deutron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 m in a plane perpendicular to magnetic field B. The kinetic energy of the proton that describes a circular orbit of radius 0.5 m in the same plane with the same B is
25 keV
50 keV
200 keV
100 keV
A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by another wire of 1 mm diameter carrying same current. The strength of magnetic field far away is
twice the earlier value
same as the earlier value
one – half of the earlier value
one quarter of the earlier value
A horizontal straight wire, 10m long, extending along the east and west direction, is falling at right angles to the horizontal component of the earth's magnetic field, 0.30 x 10-4 Wbm-2. If the induced emf is 1.5 x 10-3, the velocity of the wire is
5 x10-4 ms-1
5 x 102 ms-1
50 ms-1
5 ms-1
A long solenoid has 200 turns/cm and carries a current I. The magnetic field at its centre is 5.28 x 10-2 Wbm-2. Another long solenoid has 100 turns/cm and it carries a current I/3. The value of the magnetic field at its centre is
1.05 x 10-2 Wb m-2
1.05 x 10-5 Wb m-2
1.05 x 10-3 Wb m-2
1.05 x 10-4 Wb m-2
A current carrying coil is subjected to a uniform magnetic field. The coil will orient so that its plane becomes
inclined at 45o to the magnetic field
inclined at any arbitrary angle to the magnetic field
parallel to the magnetic field
perpendicular to magnetic field
A coil has an area of 0.05 m2 and has 800 turns. After placing the coil in a magnetic field of strength 4 x 10-5 Wbm-2, perpendicular to the field, the coil is rotated by 90o in 0.1s.The average emf induced is
zero
0.016 V
0.01 V
0.032 V
A uniform magnetic field acts 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 electrons is doubled, then the radius of the circular path will be
2.0 cm
0.5 cm
4.0 cm
1.0 cm