In a Kundt's tube apparatus, a steel rod of length 1.0 m is clamped...

For the steel rod clamped at the centre and vibrating in its fundamental mode, the centre is a node and the ends are antinodes.

Length of the rod, $L = \dfrac{\lambda_{\text{steel}}}{2}$

$\lambda_{\text{steel}} = 2L = 2 \times 1.0 = 2.0 \text{ m}$

Speed of sound in steel, $v_{\text{steel}} = f \lambda_{\text{steel}} = 2600 \times 2.0 = 5200 \text{ m/s}$

In the Kundt's tube, the distance between consecutive heaps of lycopodium powder represents the distance between consecutive nodes of the standing wave in air.

$\dfrac{\lambda_{\text{air}}}{2} = 6.5 \text{ cm} = 0.065 \text{ m}$

$\lambda_{\text{air}} = 2 \times 0.065 = 0.13 \text{ m}$

Speed of sound in air, $v_{\text{air}} = f \lambda_{\text{air}} = 2600 \times 0.13 = 338 \text{ m/s}$