Question

4. a) Define the elastic modulus. Explain the different types of elastic modulus.

b) State and explain Einstein's Photoelectric Effect theory.

c) If 12𝑁 force is applied to a fluid of cross-section 5.34 𝑐𝑚2 with a shearing rate of

0.7 𝑠

−1

then find the viscosity of the fluid.

Answer 1

a) The elastic modulus is the property of materials to withstand elastic deformations. There are Young's modulus (to withstand extension/contraction), Shear modulus (withstand shear), and Bulk modulus (withstand buckling).

b) Metals emit photo electrons as quanta of light of the corresponding wavelength value hit the surface of the metal.

с) The viscosity is

$$\mu=\frac F{Au}=31.100\text{ kPa}·\text s.$$