A simple pendulum of length 1 m, and energy 0.2 J, oscillates with an amplitude 4 cm. When its length is doubled then the energy of oscillation will be

Options

A. 0.04 J
B. 0.1 J
C. 0.02 J
D. 0.8 J

Answer

B

Explanation

`E_(1)=(1)/(2)momega^(2)A^(2)=(1)/(2)(mgA^(2))/(l_(1))`
`therefore E_(1)prop(1)/(l_(1))andE_(2)=(1)/(l_(2))`
`(E_(2))/(E_(1))=(l_(1))/(l_(2))=(1)/(2)`
`therefore E_(1)=(0.2)/(2)=0.1J`