The force `(F)`- extension `(lamda)` graph shows that the strain energy stored in the material under test, for an extension of `4mm`, is greater than which of the following values?

Options

A. `80mJ`
B. `60mJ`
C. `40mJ`
D. none of these

Answer

C

Explanation

Area under the curve represents strain energy stored and it is greater than `40mJ` Area under curve (straight line)
`=(1)/(2)Fl`
`=(1)/(2)(20)(4xx10^-3)J=40mJ`