The formation of a dipole is due to two equal and dissimilar point charges placed at a
short distance
long distance
above each other
none of the above
Current is flowing in a coil of area A and number of turns N, then magnetic moment of the coil, M is equal to
NiA
Ni/A
N2Ai
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
The magnetic field at a distance r from a long wire carrying current I is 0.4 T. The magnetic field at a distance 2r is
0.2 T
0.8 T
0.1 T
1.6 T
A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will
continue to move due east
move in a circular orbit with its speed unchanged
move in a circular orbit with its speed increased
gets deflected vertically upwards
Magnetic field due to 0.1 A current flowing through a circular coil of radius 0.1m and 1000 turns at the centre of the coil is
2 × 10-4 T
6.28 × 10-4 T
9.8 × 10-4 T
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 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
A magnet is allowed to fall through a metallic ring. During fall, its acceleration is
less than g
equal to g
greater than g
equal to 2g
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
