In sum and difference method in vibration magnetometer, the time period is more if ____.
Similar poles of both magnets are on same sides
Opposite poles of both magnets are on same sides
Both magnets are perpendicular to each other
Nothing can be said
To compare magnetic moments of two magnets by vibration magnetometer, 'sum and difference method' is better because ____.
Determination of moment of inertia is not needed which minimizes the errors
Less observations are required
Comparatively less calculations
All the above
Two magnets A and B are identical in mass, length and breadths but have different magnetic moments. In a vibration magnetometer, if the time period of B is twice the time period of A. The ratio of the magnetic moments of the magnets is ____.
A magnetic needle suspended horizontally by an un spun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from ____.
The torsion of the silk fibre
The force of gravity
The horizontal component of earth's magnetic field
All the above factors
At two places A and B using vibration magnetometer, a magnet vibrates in a horizontal plane and its respective periodic time are 2 s and 3 s and at these places the earth's horizontal components are HA and HB respectively. Then the ratio between HA and HB is ____.
9 : 4
3 : 2
4 : 9
2 : 3
Two short magnets having magnetic moments in the ratio 27 : 8, when placed on opposite sides of a deflection magnetometer, produce no deflection. If the distance of the weaker magnet is 0.12 m from the centre of deflection magnetometer, the distance of the stronger magnet from the centre is ____.
0.06 m
0.08 m
0.12 m
0.18 m
The magnet of a vibration magnetometer is heated so as to reduce its magnetic moment by 19%. By doing this the periodic time of the magnetometer is ____.
Increase by 19%
Decrease by 19%
Increase by 11%
Decrease by 21%
A tangent galvanometer has a coil of 25 turns and radius of 15 cm. The horizontal component of the earth’s magnetic field is 3 ( 10–5 T. The current required to produce a deflection of 45o in it, is ____.
0.29 A
1.2 A
3.6 ( 10–5 A
0.14 A
The error in measuring the current with a tangent galvanometer is minimum when the deflection is about ____.
0o
30o
45o
60o
The period of oscillations of a magnet is 2 s. When it is remagnetised so that the pole strength is 4 times its period is ____.
4 s
2 s
1 s
1/2 s