Question

solve this properly ​

Answer 1

$\huge{ \underline{ \underline{ \green{ \sf{ Detailed \: Answer :}}}}}$

• To find: the time period of the combination
• time period of oscillation in a vibration magnetometer,T = 2 seconds

we know that , time period of oscillation of magnet ;

T = 2π √I/(MB)

Where , I = moment of inertia of magnet

M = magnetic moment

Moment of Inertia of magnet

$I = \frac{1}{12} ml {}^{2}$

When it cut into three equal parts ,

the length of each piece of magnet is l/3

↪Moment of Inertia of the combination

$I'= \frac{1}{12} \times \frac{m}{3} \times (\frac{l {}^{} }{3} ) {}^{2} \times 3$

$= \frac{ml {}^{2} }{9×12}$

$I'= \frac{I}{9}$

${\red{\boxed{\large{\bold{Magnetic\: moment = pole\: strgenth × length}}}}}$

$M'= m \times \frac{l}{3} \times 3$

$M'= M$

$T' = 2\pi \sqrt{ \frac{I'}{M\times B} }$

$T'= 2\pi \sqrt{ \frac{ \frac{I}{9} }{MB} }$

Now divide i.e T'/T

$T'= \frac{t}{3}$

$T'= \frac{2}{3}$

∴ correct option B) 2/3 sec

Answer 2

Answer:

Option B is yr answer.

Explanation:

Hope it helps:))