90 76 A current carrying loop is placed in a uniform
Last updated: 6/10/2023
90 76 A current carrying loop is placed in a uniform magnetic field The torque acting on it does not depend upon a area of loop c magnetic field b value of current d None of these 77 A circular coil of 70 turns and radius 5 cm carrying a current of 8 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1 5 T The field lines make an angle of 30 with the normal of the coil then the magnitude of the counter torque that must be applied to prevent the coil from turning is a 33 Nm b 3 3 Nm c 3 3 x 10 2 Nm d 3 3 x 10 Nm 78 A circular coil of 25 turns and radius 12 cm is placed in a uniform magnetic field of 0 5 T normal to the plane of the coil If the current in the coil is 6 A then total torque acting on the coil is a zero b 3 4 Nm c 3 8 Nm d 4 4 Nm 79 The final torque on a coil having magnetic moment 25 A m in a 5 T uniform external magnetic field if the coil rotates through an angle of 60 under the influence of the magnetic field is a 216 5 Nm b 108 25 Nm d 258 1 N m c 102 5 N m 80 The magnitude of torque experienced by a square coil of side 12 cm which consists of 25 turns and carries a current 10 A suspended vertically and the normal to the plane of coil makes an angle of 30 with the direction of a uniform horizontal magnetic field of magnitude 0 9 T is a 1 6 Nm c 1 4 N m b 1 2 N m d 1 8 Nm 81 A coil having magnetic moment 15 A m placed in a uniform magnetic field of 4 T in the horizontal direction exists such that initially the axis of coil is in the direction of the field If the coil is rotated by 45 and the moment of inertia of the coil is 0 5 kg m then the angular speed acquired by the coil is a 20 rad sl c 8 34 rad s b 10 rad s d 4 5 rad s 82 The gyromagnetic ratio of an electron in sodium atom is a depending upon the atomic number of the atom b depending upon the shell number of the atom c independent of that orbit it is in d having positive value 83 Gyromagnetic ratio is the ratio of magnetic moment H to the orbital angular momentum 1 Its numerical value for an electron is given by a 8 8 x 10 2 C kg c 1 6 x 10 19 C kg 1 24 84 What is the correct value of Bohr magneton b 9 27 x 10 Am d 9 27 10 Am a 8 99 x 10 24 A m c 5 66 x 10 24 Am THE MOVING COIL GALVANOMETER 85 In a moving coil galvanometer the deflection 0 in the scale by a pointer attached to the spring is N NA KAB kB NAB a mtG Objective NLEH P b 8 8 x 10 Ckg d 6 67 x 10 Ckg c b d NAB kl 86 Two moving coil metres M and My have the following particular R 10 92 N 30 A 3 6x 10 m B 0 251 R 1492 N 42 A 1 8 x 10 m B 0 507 The spring constants are identical for the two mette What is the ratio of current sensitivity and voltage sensitivity of My to M a 1 4 1 b 1 4 0 a 0 025 2 c 0 035 2 c 2 8 2 d 28 0 87 If the current sensitivity of a galvanometer s doubled then its voltage sensitivity will be a doubled b halved d four times c unchanged 88 A moving coil galvanometer can be converted into an ammeter by a introducing a shunt resistance of large value in series b introducing a shunt resistance of small value in parallel c introducing a resistance of small value in series d introducing a resistance of large value in parallel 89 A galvanometer of resistance 70 2 is converted to an ammeter by a shunt resistance r 0 03 92 The value of its resistance will become b 0 022 2 d 0 030 2 90 If the galvanometer current is 10 mA resistance of the galvanometer is 40 22 and shunt of 22 is connected to the galvanometer the maximum current which can be measured by this ammeter is a 0 21 A b 2 1 A c 210 A d 21 A 91 A galvanometer of resistance 40 52 gives a deflection of 5 divisions per mA There are 50 divisions on the scale The maximum current that can pass through it when a shunt resistance of 2 92 is connected is 92