Materials Science Multiple Choice Questions & Answers (MCQs) on “Impact Fracture Tests”.
1. What is the unit of impact strength?
a) N/m
b) MN/m
c) MN/m2
d) N/m2
Answer: c
Clarification: The SI Unit for impact strength is expressed as MN/m2. The unit in numerator is taken in mega newton as the force acting is very high in case of impact strength.
2. Which of the following properties is impact strength indicative of?
a) Elasticity
b) Hardness
c) Stiffness
d) Toughness
Answer: d
Clarification: Impact strength is indicative of toughness of material and is given by how much energy the material can absorb while going through plastic deformation.
3. Which of the following is false?
a) Notch is a sudden change in section of a material
b) Stress concentration is produced due to notches
c) Notches change the stress applied to the body
d) Smaller the tip of the notch, less the increase in stress
Answer: d
Clarification: A notch is a sudden change in section of a material and stress concentrations are produced due to it. The smaller the tip of a notch the larger is the increase in stress.
4. Which of the following is not notch sensitive?
a) Carbon
b) Steel
c) Plastic
d) FCC metal
Answer: d
Clarification: Tendency of a material to behave as a brittle material in presence of a notch is termed as notch sensitivity. Carbons, steels and plastics which are notch sensitive while FCC metals aren’t notch senitive.
5. Charpy test is not a type of impact test.
a) True
b) False
Answer: b
Clarification: Charpy and Izod test are the two standard testing methods in case of impact fracture tests.
6. What is the angle of a standard notch?
a) 10°
b) 20°
c) 45°
d) 30°
Answer: c
Clarification: As standard notch which is made on the material during impact fracture testing has an angle of 45°. The type of notch used in case of Charpy and Izod test is V-notch.
7. What is the dimension of material used in case of Izod test?
a) 10 mm * 10 mm * 75 mm
b) 10 mm * 10 mm * 65 mm
c) 5 mm * 5 mm * 75 mm
d) 5 mm * 5 mm * 65 mm
Answer: a
Clarification: In Izod test the specimen is taken of the dimension 10 mm * 10 mm * 75 mm where the width and breadth of the material are 10 mm and 10 mm respectively while the length is 75 mm.
8. What is the dimension of material used in case of Charpy test?
a) 10 mm * 10 mm * 55 mm
b) 10 mm * 10 mm * 65 mm
c) 5 mm * 5 mm * 55 mm
d) 5 mm * 5 mm * 65 mm
Answer: a
Clarification: In Charpy test the specimen is taken of the dimension 10 mm * 10 mm * 55 mm where the width and breadth of the material are 10 mm and 10 mm respectively while the length is 55 mm.
9. The direction of a blow of hammer is opposite to the notch section in case of Izod test.
a) True
b) False