Question

JEE Main-2020, Online question.​

Answer 1

Answer:

4th option is correct

Explanation:

Let the elongation in the spring be x

So, radius =(l0+x)

⇒Kx=mω2r

⇒Kx=mω2(l0+x)

⇒(xl0+1)=mω2k

⇒xl0=mω2k−1=mω2k−mω2

⇒x=k−mω2l0mω2      (∵k>>mω2 given )

So, mω2 tends to zero compare to K.

⇒l0x=kmω2