Magnetic Field Questions and Answers

A wire loop is rotated in a magnetic field The frequency of change of direction of the induced e m f is a four times per revolution b six times per revolution c once per revolution LAN Moul IEET 10

2 At a point A on the earth s surface the angle of dip 8 25 At a point B on the earth s surface the angle of dip 8 25 We can interpret that 1 A and B are both located in the northern hemisphere 2 A is located in the southern hemisphere and B is located in the northern hemisphere 3 A is located in the northern hemisphere and B is located in the southern hemisphere 4 A and B are both located in the southern hemisphera 45

y A conducting wire is bent in the form of a parabola y 2x carrying a current i 2A as shown in the figure The wire is placed in a uniform magnetic field B 4K The magnetic force on the wire is A 161 C 32i B 32i D 16i 2m 0 X

Magnetic dipole moment of Het hydrogen like atoms in the ground state will be g is Bohr magneton 1 zero 3 HB 2 HB 2 3 4 B

A straight wire of diameter of 0 5 mm carrying a current of 1A is replaced by another wire of 1mm diameter carrying the same current The strength of magnetic field far away is unchanged B quarter of its earlier value twice the earlier value half of the earlier value D A C

Ans 0 8 Nm A square coil of side 10 cm has 20 turns and carries a current of 12 A The coil is suspended vertically the normal to the plane of the coil makes an angle of 30 with the direction of a uniform horizontal magnetic field If the torque experienced by the coil equals 0 96 N m find the magnitude of the magnetic field C B S E 2010 S Ans 0 8 TI

particle of m and charge q enter with velocity v in region where magnetic field in only right of PQ line of magnitude B Find magnitude of change in velocity V 3 Opiul 2 2V 4 Fooso O 3 V 2 4 zero

The potential difference across a 10 H inductor as a function of time is shown in the figure At t 0 current is zero Then A The current in the inductor at t 6 sec is 3 amp B The current in the inductor at t 1 sec is 1 4 amp C The current in the inductor at t 4 sec is 5 2 amp D The variation of current versus time is parabola V Volts 10 V 0 10 2 6 sec

1 Magnetic flux is a scalar quantity 2 The unit for magnetic flux is Weber 3 Magnetic flux has direction 4 The magnitude of the magnetic flux value does not depend on the area The exact statement about magnetic flux

A charge moving with constant velocity produces 1 Only electric field 2 Only magnetic field 3 Both electric and magnetic field and also radiates 4 Both electric and magnetic field and does not radiates

A long straight wire carrying a current of 30 A is placed in an external uniform magnetic field of induction 4 x 104 T The magnetic field is acting parallel to the direction of current The magnitude of the resultant magnetic induction in tesla at a point 2 0 cm away from the wire is uo 4 x 10 7 H m hollis B 3 10 4 C 5 x 10 4 D 6 x 10 4 A 10 4 81

Two forces are applied to a 5 0 kg object and it accelerates at a rate of 2 0 m s2 in the positive y direction If one of the forces acts in the positive x direction with magnitude 12 0 N find the magnitude of the other force

A particle of charge q and mass m starts moving from origin under the action of an electric field E Ei and B Boi with velocity v v The time after which its speed becomes 2v is 1 2 3 4 2mvo qEo 2B 9 mvo 3 Boq mvo 3 mvo

11 Magnetic field at the centre O due to the give structure is 1 3 NE Mol 3 1 4R 2 T O Mol 3 1 R 2 O R M 3 1 2R Moll 4 AR 2 3 0

A circular flexible current loop of radius R carrying current is placed in an inward magnetic field B If we spin the loop clockwise with angular speed w then tension in string Assume the mass of the loop is m XX XXX 1 Is zero 2 Is more than IBR 3 Is less than iBR X XB X X X ad on rotation

3 A steady current is set up in a network composed of wires of equal resistance and length d as shown in Figure What is the magnetic field at the centre P B C a H Ho 21 4x d E P D G F c 0 Pamprayed Grank b Ho 31 4x 2d d Ho Onl 4n d