Speed of a transverse wave on a straight wire (mass 6.0 g, length 60 cm and area of cross-section 1.0 mm2) is 90 ms–1. If the Young's modulus of wire is 16 × 1011 Nm–2, the extension of wire over its natural length is :
(1) 0.02 mm
(2) 0.04 mm
(3) 0.03 mm
(4) 0.01 mm