Free Deformation and Elasticity MCQs with Answers
17 Deformation and Elasticity MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Deformation and elasticity describe how solids change shape or volume under an applied force and return to their original form when the force is removed. Work includes stress, strain, Hooke’s law, elastic limit, Young’s modulus and elastic potential energy, while elastic deformation must be distinguished from permanent plastic deformation.
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11. The applied force which the solid can withstand without breaking is called
- A. Stiffness of solids
- B. Strength of solid
- C. Ductility of solids
- D. Toughness of solid
Explanation: Strength measures how much stress can be applied to an element before it deforms permanently or fractures.
Correct answer: Strength of solid12. The substances which undergo deformation with a small force are called;
- A. Elastic substances
- B. Inelastic substances
- C. Diamagnetic substances
- D. Ductile substances
Explanation: Elastic substances are materials that undergo deformation when subjected to small forces, but they can return to their original shape and size once the force is removed.
Correct answer: Elastic substances13. The ratio of volumetric strain to volumetric stress called:
- A. compressibility
- B. young's modulus
- C. bulk's modulus
- D. shear's modulus
Explanation: Compressibility is the ratio of volumetric strain to volumetric stress. It is the inverse of bulk's modulus. Its SI unit is the pascal. Strain: A force tending to pull or stretch something to an extreme or damaging degree Stress is a quantity that describes the magnitude of the forces that cause deformation (strain).
Correct answer: compressibility14. The substance that undergoes plastic deformation until it breaks is:
- A. ductile substance
- B. brittle substance
- C. plastic substance
- D. all of these
Explanation: The substance which undergoes plastic deformation until it breaks is a DUCTILE SUBSTANCE. Therefore, option 'A' is correct.
Correct answer: ductile substance15. The spring constant of a spring is k. If the spring is cut into two halves then the spring constant of one of the halves is:
- A. k + 2
- B. k/2
- C. 2k
- D. k
Explanation: According to Hooke's Law, the force exerted by a spring is given by F = -kx, where k is the spring constant and x is the displacement. The spring constant is a measure of the spring's stiffness. When a spring is cut into two equal halves, each half becomes stiffer because the same force is now applied over a shorter distance. Therefore, the spring constant of each half becomes twice the original, or 2k. The other options are incorrect because they do not accurately reflect this relationship. Option A incorrectly adds a constant, Option B incorrectly assumes the spring constant is halved, and Option D assumes the spring constant remains unchanged.
Correct answer: 2k16. A spring obeying Book's law has an unstretched length of 50 mm and a spring contant of 400 Nm-01. What is the tension in the spring when its overall length is 70mm?
- A. 8.0N
- B. 28N
- C. 160N
- D. 400N
Explanation: According to Hooke's Law, the force F exerted by a spring is directly proportional to the displacement x from its equilibrium position, which can be expressed as F = kx.In this problem, the unstretched length of the spring is 50 mm. The stretched length is given as 70 mm, so the displacement x is 70 mm - 50 mm = 20 mm, which is 0.02 meters.The spring constant k is given as 400 N/m. Therefore, the tension in the spring is F = 400 N/m * 0.02 m = 8 N.Options B, C, and D are incorrect because they either miscalculate the displacement, misapply the spring constant, or misunderstand the relationship given by Hooke's Law.
Correct answer: 8.0N17. A spring obeying Hook's law has an unstretched length of 50mm and a spring constant of 400 Nm -1. What is the tension in the spring when its overall length is 70mm?
- A. 8.0N
- B. 28N
- C. 160N
- D. 400N
Explanation: In order to find the displacement x we subtract the untstrected length from the overall length. The stretched length is equal to displacement x.70-50=20F = kxF = 20*10-3*400F = 8 N
Correct answer: 8.0N