A wire suspended vertically from one of the its ends is stretched by attaching a weight of 200 N to the lower end. The weight stretches the wire by 1 mm. then the elastic energy stored in the wire is

Options

A. 0.2 J
B. 10 J
C. 20 j
D. 0.1 J

Answer

d

Explanation

Elastic energy stored in the wire is
`U =( 1)/(2) xx` stress `xx` strain `xx` volume
`= (1)/(2) xx (F)/(A) xx (Delta l)/(l) xx Al = (1)/(2) F Delta l`
or `U = (1)/(2) xx 200 xx 1 xx 10^(-3) = 0.1 J`