When two springs A and B with force constants \(k_A\) and \(k_B\) are stretched by the same force, then the respective ratio of the work done on them is
Show Hint
For same force, softer spring (smaller \(k\)) stores more energy.
Concept:
Work done in stretching a spring:
\[
W = \frac{1}{2}kx^2
\]
Also, from Hooke’s law:
\[
F = kx \Rightarrow x = \frac{F}{k}
\]
Step 1: Substitute \(x = \frac{F}{k}\) into work formula.
\[
W = \frac{1}{2}k \left(\frac{F}{k}\right)^2
\]
Step 2: Simplify expression.
\[
W = \frac{1}{2}k \cdot \frac{F^2}{k^2} = \frac{F^2}{2k}
\]
Step 3: Relation between work and spring constant.
\[
W \propto \frac{1}{k}
\]
Step 4: Take ratio.
\[
\frac{W_A}{W_B} = \frac{1/k_A}{1/k_B} = \frac{k_B}{k_A}
\]
Step 5: Conclusion.
\[
\boxed{k_B : k_A}
\]