This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Torsional Tests”.
1. Which of the following cannot be determined using a torsion test?
a) Modulus of elasticity in shear
b) Torsion yield strength
c) Modulus of rupture
d) Young’s modulus
Explanation: Modulus of elasticity in shear, torsion yield strength and modulus of rupture can all be determined by performing torsion test on material.
2. What is the use of weight head in a torsion testing equipment?
a) Holding the job only
b) Holding the job and applying twisting moment
c) Holding the job and measuring the twisting moment
d) It is not a part of torsion testing equipment
Explanation: The main job of weight head is to hold the job and measure the twisting moment.while twisting head holds the other end of job and applies twisting moment.
3. Which of the following is used to measure how much the specimen is twisted?
Explanation: Troptometer is an instrument which is used for measuring the angular distortion of the material. Mocrometer and vernier callipers are used to measure length. Tropometer measures amount of torsion for a bone.
4. Torsional stress multiplied with original cross sectional are is:
a) Maximum twisting load
b) Minimum twisting load
c) Minimum shear load
d) Yield shear load
Explanation: Torsional stress is given by the ratio of maximum twisting load and original are of cross section of the material. Therefore, torsional stress multiplied with original cross sectional gives us maximum twisting load.
5. Plastic deformation can only occur in case of torsional force.
Explanation: The above given statement is false as plastic deformation can occur in case of tensile, compressive and torsional load after a point. After this point, the body cannot recover its original shape.
6. What is the unit of polar moment of inertia?
Explanation: Polar moment of inertia denoted by J, is given by integration of radius square with respect to small area of cross-section. Hence the unit is (m)(m)(m)2 which is equal to m4.
7. Shear stress on a solid bar and hollow bar is same for given dimension.
Explanation: Shear stress for a hollow bar and a solid bar are different dimensions as the hollow bar has two dimensions, outer and inner radius because of which calculation is different than the solid bar which has only one diameter.
8. In which of the following the angle of twist increases fast for a small amount of torque?
a) Cold working condition
b) Hot working condition
c) Warm working condition
d) The increase is the same for cold working, hot working and warm working
Explanation: When the torsion test is conducted in hot working, it is observed that for a slight change in torque on the given specimen the angle of twist increase fast as the material becomes soft at hot working temperature.
Sanfoundry Global Education & Learning Series – Materials Science.
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