Elasticity

Question 1

Main cause of elasticity?

Answer 1

On application of force on solids displacement of atoms/molecules takes place which changes the inter-atomic/molecular distances

On removal of these forces inter-atomic/molecular forces cause atoms/molecules to return to their equilibrium positions

Question 2

Stress =

Answer 2

F/A

Question 3

Types of stress

Answer 3

Longitudinal stress

Tangential stress

Question 4

Types of lmgitudinal stress

Answer 4

Tensile stress
Compressive stress
Volumetric stress

Question 5

Strain =?

Answer 5

/\x /X

Question 6

Types of strain

Answer 6

Linear= /\l /L
Volumetric = /\V /V
Shearing(change in shape) = phi (tangential force)

Question 7

Hooke’s Law

Answer 7

Stress ~ Strain

E = Stress/Strain

Question 8

Young’s Modulus of Elasticity =

For solids

Answer 8

Y = (F/A) / (/\l /L)

Question 9

Bulk Modulus =

For fluids

Answer 9

-p /( /\V/V)

Negative sign signifies that for increase in pressure volume decreases

Question 10

Shearing Modulus =

Answer 10

N = (F/A)/phi

= FL/Ax

Question 11

Compressibility =

Answer 11

1/bulk modulus

Question 12

Poisson’s Ratio

Answer 12

Sigma = -( /\d/d) / (/\l/l)

= transverse strain/longitudinal strain

Theoretical value
-1

Question 13

Relation between

Young’s ,Bulk and shearing modulus

Answer 13

9/Y = 3/n + 1/B

Y=2n(1+sigma)
Y=3B(1-2sigma)

Question 14

Volume elasticity of a gas under isothermal conditions=

Answer 14

Pressure

Question 15

Adiabatic elasticity of gas =

Answer 15

Coefficient of specific heat x pressure