EAMCET Engineering 2003 Solved Paper

Time period of magnet in vibration magnetometer,
T=2π√‌

I

MH

First case, T1=2π√‌

I1+I2

M′H

where, M= resultant magnetic moment of two magnets
Here, two identical magnets are placed perpendicular to each other.
‌∴‌‌I1=I2=I‌ (Let) ‌
‌‌ and ‌‌‌M′=√M2+M2=M√2
‌∴‌‌T1=2π√‌

2I

√2MH

‌25∕4=2π√‌

2I

√2MH

. . . (i)
When one magnet is removed, then time period,
T2=2π√‌

I

MH

. . . (ii)
On dividing Eq. (i) by Eq. (ii), we get
‌

25∕4

T2

=√‌

2

√2

=√√2
‌

25∕4

T2

‌=21∕4
T2‌=‌

25∕4

21∕4

=2 s