To solve this problem, we will start by defining each of the variables given and proceed to find the modulus of elasticity of the object. We will calculate the deformation per unit of elastic volume and finally we will calculate the net energy of the system. Let's start defining the variables
Yield Strength of the metal specimen

Yield Strain of the Specimen

Diameter of the test-specimen

Gage length of the Specimen

Modulus of elasticity



Strain energy per unit volume at the elastic limit is



Considering that the net strain energy of the sample is




Therefore the net strain energy of the sample is 
Friction is a force that oppose other forces and can slow them down
Answer:
The distance from the central bright spot are
and
.
Explanation:
Given that,
Wavelength = 490 nm
Distance y= 15 mm
Length L=1.6 m
New wavelength = 670
We need to calculate the distance from the central bright spot
Using formula of distance


Put the value into the formula



We need to calculate the distance from the central bright spot for new wavelength
Using formula of distance

Put the value into the formula



Hence, The distance from the central bright spot are
and
.