This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Impact Fracture Tests”.
1. What is the unit of impact strength?
a) N/m
b) MN/m
c) MN/m2
d) N/m2
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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°
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: 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
View Answer
Explanation: The above statement is false as the direction of the blow of hammer is opposite to the notch section in case of Charpy test and the direction are same in case of the Izod test.
10. Which of the following is the Charpy V impact strength for annealed pure copper?
a) 30 J
b) 31 J
c) 32 J
d) 34 J
View Answer
Explanation: The value of Charpy V impact strength of annealed pure copper is experimentally found out to be 34 J.
Sanfoundry Global Education & Learning Series – Materials Science.
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