Answer:
All the given option is false.
Explanation:
A)
This is not true for all the materials like composite because the Poisson ratio for composite material can be negative that is why positive tensile stress may produce positive lateral strain.
B)
This is not true for all the material because the Poisson ratio for some material can be positive that is why positive tensile stress may produce negative lateral strain.
C)
The explanation is same as option A.
D)
This is not true for all the materials ,It is valid only up to elastic limit .After the elastic limit the strain and stress does not follow linear path.
E)
This is not true for all the materials because some materials like composite is having negative value of Young's modulus.
Therefore all the given option is false.
Answer:
Number of photons travel through pin hole=
Explanation:
First we will calculate the energy of single photon using below formula:
Where :
h is plank's constant with value 
c is the speed of light whch is
λ is the wave length = 532nm
E=
J
Number of photons emitted per second:
Number of photons emitted per second=
=
Where:
A-hole is area of hole
A-beam is area of beam
d-hole is diameter of hole
d-beam is diameter if beam
=
=
=
Number of photons travel through pin hole=
Number of photons travel through pin hole=
Answer:
The correct answer is (a), heating and soaking at a temperature above the austenitizing level followed by rapid cooling.
Explanation:
Tempering is a heat treatment that is performed to change microstructure of steel <em>and increase it's hardness.</em>
It is done by heating above the austenitizing level, because for this heat treatment it's necesary to heat the steel to get <em>austenite structure</em> that is the <em>alotropic form of gamma iron.</em>
The procedure of tempering, continues with rapid cooling, because this way you get the microstructure with the best hardness properties, that is <em>martensite.</em>
The first one is B. I think and the second one is A.
