Question

Diamon has a Young's modulus pf about 800GPa and density of 2.3g/cm3.

Lead has a Young's modulus of about 15 GPa and a density of 11.4g/cm3.

What is the velocity of sound in these two rather different materials? How do these velocities compare with the velocity of sound in air? What is the velocity of sound in vacuum?

Answer 1

Velocity of sound in a medium is given by-

For diamond-

Modulus of elasticity =800GPa=800 x 10⁹ Pa

density=2.3g/cc=(2.3x10^-3)kg/(10^-6)m³=2.3x10³kg/m3

For lead-

Modulus of elasticity for lead=15x 10⁹Pa

Density=11.4g/cc=(11.4x10^-3)kg/(10^-6)m³=11.4x10³kg/m3

velocity of sound in air at 27⁰C is approximately 340m/s.

so velocities in diamond and lead is very much larger than velocity in air.velocity in diamond is maximum among all these 3 media.

Sound can not travel in vacuum because it requires a material medium to propagate.so velocity in vacuum is zero.

answered by: anonymous