Paragraph : A scientist was asked to find the height of the roof of a dome shaped hall. He took a spherical ball of radius 20 cm which he suspend with the string from the roof of dome. The height of the ball above the ground was 5 cm when suspended. He noted the time of 20 oscillations to be 100 s. The length of the string used to suspend the bob of pendulum is :

Paragraph : A scientist was asked to find the height of the roof of a

1.	Paragraph : A scientist was asked to find the height of the roof of a dome shaped hall. He took a spherical ball of radius 20 cm which he suspend with the string from the roof of dome. The height of the ball above the ground was 5 cm when suspended. He noted the time of 20 oscillations to be 100 s. The length of the string used to suspend the bob of pendulum is :
Answer» 6.39 m 6.14 m 6 m 6.44 m. Solution :`T=2pi sqrt((l)/(g))impliesl=(GT^(2))/(4pi^(2))=(20xx5^(2))/(4xx(3.14)^(2))=6.34` m. length of STRING used `=l-` radius of bob `=6.34-.20` `=6.14` m. So CORRECT choiceis(B).

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