Slope of stress-strain curve in elastic deformation region is a. plastic modulus b. poisson's ratio c. elastic modulus d. none the these a) all of these

c) Elastic Modulus

Explanation

As we know that when deformation is under elastic limit then stress applied to the given material is proportional to the strain developed in it

So here we can say that since they both are directly proportional to each other so the proportionality constant here is known as Modulus of elasticity.

So we can say it is given as

so now if we draw a graph between between stress and strain then it must be a straight line and the the slope of this straight line is given as

So here correct answer will be

c) Elastic Modulus

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.