Given,

Length of the steel rod, L = 100 cm = 1 m

Fundamental frequency of vibration, f = 2.53 kHz = 2.53 × 10³ Hz When the rod is plucked at its mid-point, an antinode (A) is formed at its centre, and nodes (N) are formed at its two ends.

The distance between two successive node is λ/2.

∴ L = λ/2

⇒ λ = 2L

⇒ λ = 2 × 1 m

⇒ λ = 2 m

The speed of sound in steel is given by

v = fλ

⇒ v = 2.53 × 10³ Hz × 2 m

⇒ v = 5.06 × 10³ m s^-1

⇒ v = 5.06 km s^-1

NOTE: A node is a point along a standing wave where the wave has minimum amplitude. The opposite of a node is an anti-node, a point where the amplitude of the standing wave is a maximum.