• # question_answer A spring when stretched by 2 mm its potential energy becomes 4 J. If it is stretched by 10 mm, its potential energy is equal to                          [BCECE 2003] A)             4 J       B)             54 J C)             415 J   D)             None

$U=\frac{1}{2}k{{x}^{2}}$ if x becomes 5 times then energy will become 25 times i.e. $4\times 25=100\,J$