Question

3. Copper has rigidity modulus 4x1010 Nm2 , bulk modulus 1.2x1011 Nm2 and density 9g/cm3. The velocity of longitudinal wave when set up in a solid copper rod is nearly.​

Answer 1

Answer:

Explanation:

Rigidity modulus =4×10  

10   N/m  2

 

           Bulk modulus =1.2×10  11   N/m  2

    Density =9 g/cm  3

Velocity =  ρ K+  3 4  η

​   =  9000 1.2×10  11  +  3 4

​  (4×10  10  ) ≈4389m/s

Answer 2

Given:

Rigidity modulus = 4 × 10¹⁰ N/m²

Bulk modulus = 1.2×10¹¹ Nm²

Density = 9g/cm³

To find:

Velocity of longitudinal wave

Solution:

Rigidity modulus, η = 4×10¹⁰ Nm⁻²

Bulk modulus, K = 1.2×10¹¹ Nm⁻²

Density, d = 9g/cm²

Formula used to find density,

  $\text velocity = \sqrt{\tfrac{K + \tfrac{4}{3}\eta }{d}}$

by putting all the values of K, η and d , we get

$\text velocity = \sqrt{\tfrac{1.2 \times 10^1^1 + \tfrac{4}{3}\ \times 4 \times 10^1^0}{9000}}$

velocity = 4389m/s

so, velocity of longitudinal wave is 4389m/s