Two wires are made of the same material and have the same volume. The first wire has a cross-sectional area \(A\) and the second wire has a cross-sectional area \(3A\). If the length of the first wire is increased by \(\Delta l\) on applying a force \(F\), how much force is needed to stretch the second wire by the same amount?

The bulk modulus of a spherical object is \(B\). If it is subjected to uniform pressure \(P\), the fractional decrease in radius will be:
1. \(\frac{P}{B}\)
2. \(\frac{B}{3P}\)
3. \(\frac{3P}{B}\)
4. \(\frac{P}{3B}\)