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 straight wire of length 0.5 m and carrying a current of 1.2 A is placed in uniform magnetic field of induction 2 T. The magnetic field is perpendicular to the length of the wire. The force on the wire is :
2. 4 N
1.2 N
3.0 N
2.0 N
A galvanometer of resistance 50 Ω is connected to a battery of 3 V along with a resistance of 2950 Ω in series. A full scale deflection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions, the resistance in series should be :
5050 Ω
5550 Ω
6050 Ω
4450 Ω
Tesla is the unit of :
magnetic flux
magnetic field
magnetic induction
magnetic moment
A neutron 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
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 coil of one turn is made of a wire of certain length and then from the same length a coil of two turns is made. If the same current is passed is both the cases, then the ratio of the magnetic induction at their centers will be :
2 : 1
1 : 4
4 : 1
1 : 2
A charge moving with velocity v in X-direction is subjected to a field of magnetic induction in negative X – direction . As a result, the charge will :
remain unaffected
start moving in a circular Y – Z plane
retard along X – axis
moving along a helical path around X – axis
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
At what distance from a long straight wire carrying a current of 12 A will the magnetic field be equal to 3 x 10-5 Wb/m2?
8 × 10-2 m
12 × 10-2 m
18 × 10-2 m
24 × 10-2 m
