Questions in magnetism

Select	Question
	Time period in vibration magnetometer will be infinity at
	Twists of suspension fibre should be removed in vibration magnetometer so that
	The period of oscillation of a magnet in vibration magnetometer is 2 sec. The period of oscillation of a magnet whose magnetic moment is four times that of the first magnet is
	Moment of inertia of a magnetic needle is 40 gm-cm2 has time period 3 seconds in earth's horizontal field = $3.6 imes {10^{ - 5}}$weber/m2. Its magnetic moment will be
	Vibration magnetometer before use, should be set
	If a brass bar is placed on a vibrating magnet, then its time period
	A magnetic needle is made to vibrate in uniform field $H$, then its time period is $T$. If it vibrates in the field of intensity 4H, its time period will be
	Two bar magnets of the same mass, length and breadth but magnetic moments M and 2M respectively, when placed in same position, time period is 3 sec. What will be the time period when they are placed in different position
	To compare magnetic moments of two magnets by vibration magnetometer, 'sum and difference method' is better because
	A magnet is suspended in such a way that it oscillates in the horizontal plane. It makes 20 oscillations per minute at a place where dip angle is 30o and 15 oscillations per minute at a place where dip angle is 60o. The ratio of total earth's magnetic field at the two places is