Properties of Materials

Q. A $2m$ long bar of uniform section extends $2mm$ under limiting axial stress of $200N/m{m}^2$. What is the modulus of resilience for the bar?

1. $0.10$ Units
2. $0.20$ units
3. $10000$ units
4. $200000$ units

Q. For the coplanar concurrent system of forces as shown in the given figure, the system will be

1. in equilibrium if $|F_3|=10kN$
2. in equilibrium if $|F_3|=10\sqrt{2}kN$
3. in equilibrium if $|F_3|=20kN$
4. will not be in equilibrium whatever be the magnitude of $F_3$

Q. Creep of a material is a property indicated by

1. a time dependent strain of the material
2. elongation of the material due to changes in the material properties
3. shortening caused by shrinkage of the member
4. the decrease in the volume of the material affected by the weather conditions

Q. A square steel bar ol 50 mm side and 5 m long is subjected to a load where upon it absorbs a strain energy of 100 J. What is its modulus of resilience?

1. $\frac{1}{125}N-mm/m{m}^3$
2. $\frac{1}{125}m{m}^3/N-mm$
3. $\frac{1}{100}N-mm/m{m}^3$
4. $100m{m}^3/N-mm$

Q. Which of the following statements are correct?
1. In a ductile material elastic deformation is more predominant than plastic one.
2, Brittleness is not an absolute property of a metal.
3. Rate of loading has no influence in changing the behaviour of a metal from 'ductile' to 'brittle' at low temperatures.
4. Under hydrostatic compression, a brittle metal may change into a ductile one.

1. 1 and 2
2. 2 and 3
3. 3 annd 4
4. 2 and 4

Q. Creep is the gradual increase of

1. plastic strain with time at constant load
2. elastic strain with time at constant load
3. plastic strain with time at varying load
4. elastic strain with time at varying load

Q. A hypothetical engineering stress-strain curve shown in the figure has three straight lines PQ, QR, RS with coordinates P(0, 0), Q (0.2, 100), R (0.6, 140) and S (0.8, 130). Q is the yield point, R is the UTS point and S the fracture point.


The toughness of the material (in MJ/ $m^3$) is

1. 0.85

Q. Match List-I (Material) with List-II (Characteristic) and select the correct answer using the codes given below the lists:

List - I	List - II
A. Inelastic material	1. No plastic zone
B. Rigid plastic material	2. Large plastic zone
C. Ductile material	3. Strain is not recovered after unloading
D. Brittle material	4. Strain is zero upto a stress level and then stress remains constant.

Codes:
$ABCD$

1. $3421$
2. $3412$
3. $4321$
4. $4312$

Q. The stress-strain curve for mild steel is shown in figure given below. Choose the correct option referring to both figure and table.

Point on the graph	Description of the point
P	1.Upper yield point
Q	2.Ultimate tensile strength
R	3.Proportionality limit
S	4.Elastic limit
T	5.Lower yield point
U	6.Failure

1. P-1, Q-2, R-3, S-4, T-5, U-6
2. P-3, Q-1, R-4, S-2, T-6, U-5
3. P-3, Q-4, R-1, S-5, T-2, U-6
4. P-4, Q-1, R-5, S-2, T-3, U-6

Q. Match List-I with List-II and select the correct answer using the codes given below the lists:

List - I	List - II
A. Tenacity	1. Continues to deform without much increase of stress
B. Plasticity	2. Ultimate strength in tension
C. Ductility	3. Extension in a direction without rupture
D. Malleability	4. Ability to be drawn out by tension to a small section without rupture

Codes:
$ABCD$

1. $2143$
2. $2134$
3. $1243$
4. $1234$

Q. Some structural members subjected to long time sustained loads deform progressively with time especially at elevated temperatures. What is such a phenomenon called?

1. Fatigue
2. Creep
3. Creep relaxation
4. Fracture

Q. Consider the following statements :
1. In the infinitesimal strain theory, dilatation is taken as an invariant.
2. Dilatation is not proportional to the algebraic sum of all normal stresses.
3. The shearing modulus is always less than the elastic modulus.
Which of the above statements is/are correct?

1. $1$ Only
2. $1$ and $2$ Only
3. $2$ Only
4. $1,2$ and $3$

Q. Match List-I (Property) with List-II (Characteristic) and select the correct answer using the codes given below the lists:

List - I	List - II
A. Fatigue	1. Material continues to deform with time under sustained loading
B. Creep	2. Decreased resistance of material to repeated reversals of stress
C. Plasticity	3. Material has a high probability of not falling under reversals of stresss of magnitude below this level
D. Endurance limit	4. Material continues to deform without any further increase in stress.

Codes
$ABCD$

1. $2143$
2. $2134$
3. $1243$
4. $1234$

Q. In the engineering stress-strain curve for mild steel, the Ultimate Tensile Strength (UTS) refers to

1. Yield stress
2. Proportional limit
3. Maximum stress
4. Fracture stress

Q. Match List-I with List-II and select the correct answer using the codes given below the lists:

List - I	List - II
A. Ductility	1. Failure without warning
B. Brittleness	2. Drawn permanently over great changes of shape without rupture
C. Tenacity	3. Absorption of energy at high stress without rupture
D. Toughnesss	4. High tensile strength

Codes:
$ABCD$

1. $1243$
2. $1234$
3. $2341$
4. $2143$