Identical springs of steel and copper `(Y_("Steel") gt Y_("copper"))` are equally stretched.

Options

A.  Less work is done on copper spring.
B. Less work is done on steel spring.
C. Equal work is done on both the springs.
D. Data is incomplete.

Answer

B

Explanation

Work done, `W =(1)/(2) xx FxxDeltaL`
For a given F
`W prop DeltaL`
and `DeltaL = (FL)/(AY)`
As, F , A and L are constants
`therefore Delta L prop (1)/(Y)`
From (i) and (ii),we get
`W prop (1)/(Y)`
`therefore (W_("steel"))/(W_("copper"))=(Y_("Copper"))/(Y_("steel"))`
As `Y_("copper") lt Y_("steel")`
`therefore W_("steel")lt W_("copper")`
So, less work is done on steel spring.