NEET Physics Bulk and Rigidity Modulus and Work Done in Stretching a Wire MCQs Set A

Question. Which of the following is the correct relation? Y = Young's modulus & G = modulus of rigidity?
(a) Y > G
(b) None of these
(c) Y < G
(d) Y = G

Answer: D

Question. The isothermal bulk modulus of a gas at atmospheric pressure is
(a) 1.013 × 10⁵ N/m²
(b) 1 mm of Hg
(c) 13.6 mm of Hg
(d) 2.026 × 10⁵ N/m²

Answer: A

Question. The ratio of shearing stress to the corresponding shearing strain is called
(a) modulus of rigidity
(b) bulk modulus
(c) Young's modulus
(d) None of these

Answer: A

Question. The reciprocal of the bulk modulus is called
(a) compressibility
(b) modulus of rigidity
(c) volume stress
(d) volume strain

Answer: A

Question. Which of the following elastic moduli is used to describe the elastic behaviour of object as they respond to the deforming forces acting on them?
(a) All of these
(b) Shear modulus
(c) Young's modulus
(d) Bulk modulus

Answer: A

Question.  Select the correct statement(s) from the following.
I. Modulus of rigidity for a liquid is not zero
II. Young's modulus of a material decreases with rise intemperature
III. Poisson's ratio is unitless
(a) II and III
(b) I and II
(c) II only
(d) I only

Answer: A

Question. Which of the following statements is/are wrong?
I. Hollow shaft is much stronger than a solid rod of same length and same mass.
II. Reciprocal of bulk modulus of elasticity is calledcompressibility.
III. It is difficult to twist a long rod as compared to small rod.
(a) III only
(b) I only
(c) II and III
(d) I and II

Answer: A

Question. A metallic wire of length 2.0 m is elongated by 2.0 mm. Areaof cross-section of the wire is 4.0 mm². The elastic potentialenergy stored in the wire in elongated condition is [young's modulus of the metallic wire is = 2 X 10¹¹ N/m²]
(a) 0.83
(b) 8.23
(c) 6.23
(d) 0.63

Answer: A

Question. Assertion : Bulk modulus of elasticity (k) representsincompressibility of the material.
Reason : Bulk modulus of elasticity is proportional to change in pressure.
(a) Assertion is correct, reason is correct; reason is acorrect explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Answer: A

Question. Shearing strain is expressed by
(a) angle of shear
(b) decrease in volume
(c) angle of twist
(d) increase in volume

Answer: A

Question. When a pressure of 100 atmosphere is applied on a sphericalball, then its volume reduces to 0.01%. The bulk modulus of the material of the rubber in dyne/cm² is
(a) 1 × 10¹²
(b) 10 × 10¹²
(c) 100 × 10¹²

Answer: A

Question. A uniform cube is subjected to volume compression. If each side is decreased by 1%, then bulk strain is
(a) 0.03
(b) 0.02
(c) 0.06
(d) 0.01

Answer: A

Question. When a 4 kg mass is hung vertically on a light spring thatobeys Hooke’s law, the spring stretches by 2 cms. The workrequired to be done by an external agent in stretching this spring by 5 cms will be (g = 9.8 m/sec²)
(a) 2.450 joule
(b) 0.245 joule
(c) 4.900 joule
(d) 0.495 joule

Answer: A

Question. Assertion : Identical springs of steel and copper are equallystretched. More work will be done on the steel spring
Reason : Steel is more elastic than copper.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. If in a wire of Young’s modulus Y, longitudinal strain X isproduced, then the value of potential energy stored in its unit volume will be
(a) Y X²/2
(b) Y² X/2
(c) 2 Y X²
(d) Y X²

Answer: A

Question. The Poisson’s ratio of a material is 0.5. If a force is applied toa wire of this material, there is a decrease in the cross-sectional area by 4%. The percentage increase in the length is :
(a) 4%
(b) 2.5%
(c) 2%
(d) 1%

Answer: A

Question. The Young's modulus of the material of a wire is 2 × 10¹⁰ Nm^–2. If the elongation strain is 1%, then the energy stored in the wire per unit volume in Jm^–3 is
(a) 10⁶
(b) 10⁸
(c) 2 × 10⁶
(d) 2 × 10⁸

Answer: A

Question. A 5 metre long wire is fixed to the ceiling. A weight of 10 kgis hung at the lower end and is 1 metre above the floor. Thewire was elongated by 1 mm. The energy stored in the wiredue to stretching is
(a) 0.05 joule
(b) 100 joule
(c) 500 joule
(d) zero

Answer: A

Question. A wire suspended vertically from one of its ends isstretched by attaching a weight of 200N to the lower end.The weight stretches the wire by 1 mm. Then the elastic energy stored in the wire is
(a) 0.1 J
(b) 20 J
(c) 10 J
(d) 0.2 J

Answer: A