Question

A quartz crystal of thickness 0.001m is vibrating at resonance. Calculate the fundamental frequency. Density of quartz = 2.650×10^3 kg/m^3 and Young’s modulus for quartz = 7.9×10^10 N/m^2.

(a) 2.7299×10^6MHz

(b) 26.50×10^3Hz

(c) 2.093×10^6Hz

(d) 2.7299×10^10MHz

The question was asked in exam.

Enquiry is from Magnetostriction Effect and Magnetostriction Generator in portion Ultrasonics & Relativity of Engineering Physics I

Answer 1

The correct choice is (a) 2.7299×10^6MHz

To elaborate: Fundamental frequency = 1/(2×0.001) √((7.9×10^10)/(2.650×10^-3))

Fundamental frequency = 2.7299×10^6MHz.