JEE Physics Mechanical Properties Of Solids MCQs Set B

Question: A sphere contracts in volume by 0.01% when taken to the bottom of sea 1 km deep. Find Bulk modulus of the material of sphere

• a) 9.8 × 10¹⁰ N/m²
• b) 9.8 × 10¹¹ N/m²
• c) 1.2 × 10¹⁰ N/m²
• d) 9.8 × 10⁶ N/m²

Answer: 9.8 × 10¹⁰ N/m²

Question: A mild steel wire of length 2l meter cross-sectional area A m² is fixed horizontally between two pillars. A small mass m kg is suspended from the mid point of the wire. If extension in wire are within elastic limit. Then depression at the mid point of wire will be

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• b)

  

• c)

  

• d)

  

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Question:  A rigid bar of mass 15 kg is supported symmetrically by three wire each of 2 m long. These at each end are of copper and middle one is of steel. Young’s modulus of elasticity for copper and steel are 110 × 10⁹ N/m² and 190 × 10⁹ N/m² respectively. If each wire is to have same tension, ratio of their diameters will be

• a)

  

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• d)

  

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Question: A solid cube of copper of edge 10 cm subjected to a hydraulic pressure of 7 × 10⁶ pascal. If Bulk modulus of copper is 140 GPa, then contraction in its volume will be

• a) 5 × 10^–8 m³
• b) 4 × 10^–8 m³
• c) 2 × 10^–8 m³
• d) 10⁸ m³

Answer: 5 × 10^–8 m³

Question:  Three bars having length l, 2l and 3l and area of cross-section A, 2A and 3A are joined rigidly end to end. Compound rod is subjected to a stretching force F. The increase in length of rod is (Young’s modulus of material is Y and bars are massless)

• a)

  

• b)

  

• c)

  

• d)

  

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Question:

• a) 2.56 × 10⁴
• b) None of these
• c) 3.72 × 10²
• d) 3.72 × 10²

Answer: 2.56 × 10⁴

Question:

• a) P
• b)

  

• c)

  

• d)

  

Answer: P

More Questions..................................

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Question: A wire can sustain a weight of 15 kg. If it cut into four equal parts, then each part can sustain a weight

• a) 15 kg
• b) 30 kg
• c) 45 kg
• d) 5 kg

Answer:  15 kg

Question:

• a) 8 : 9
• b) 6 : 5
• c) 11 : 7
• d) 10 : 13

Answer: 8 : 9

Question:  A bar is subjected to axial forces as shown. If E is the modulus of elasticity of the bar and A is its crosssection area. Its elongation will be

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Question: A metal ring of initial radius r and cross-sectional area A is fitted onto a wooden disc of radius R > r. If Young’s modulus of metal is Y then tension in the ring is

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Question: A wire of length 5 m is twisted through 30° at free end. If the radius of wire is 1 mm, the shearing strain in the wire is

• a) 0.36
• b) 1°
• c) 0.18°
• d) 30°

Answer:  0.36

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Question: What is called the ratio of the breaking stress and the working stress?

• a) Power of safety
• b) Yield point
• c) Elastic after effect
• d) None of these

Answer: Power of safety

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• c) None of these
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Question: The following four wires of length L and radius r are made of the same material. Which of these will have the largest extension, when the same tension is applied?

• a) L = 100 cm, r = 0.2 mm
• b) L = 300 cm, r = 0.6 mm
• c) L = 400 cm, r = 0.8 mm
• d) L = 200 cm, r = 0.4 mm

Answer:  L = 100 cm, r = 0.2 mm

Question: The increase in pressure required to decrease the 200 L volume of a liquid by 0.008% in kPa is (Bulk modulus of the liquid = 2100 MPa is)

• a) 168
• b) 92.4
• c) 84
• d) 8.4

Answer: 168

Question: Which of the following relations is true?

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Question: A 5 m long aluminium wire (Y = 7 × 1010 Nm^–2) of diameter 3 mm supports a 40 kg mass. In order to have the same elongation in the copper wire (Y = 12 × 10¹⁰ Nm^–2) of the same length under the same weight, the diameter should now be (in mm)

• a) 2.3
• b) 5.0
• c) 1.5
• d) 1.75

Answer: 2.3

Question: Two wires of same material and radius have their lengths in ratio 1 : 2. If these wires are stretched by the same force, the strain produced in the two wires will be in the ratio

• a) 1 : 1
• b) 2 : 1
• c) 2 : 1
• d) None of these

Answer:  1 : 1

Question:

• a) 60 kg
• b) 80 kg
• c) 100 kg
• d) 40 kg

Answer: 60 kg

Question:  The hollow shaft is ____ than a solid shaft of same mass, material and length.

• a) More stiff
• b) Equally stiff
• c) None of these
• d) Less stiff

Answer: More stiff

Question: The Bulk modulus for an incompressible liquid is

• a) Infinity
• b) Between 0 and 1
• c) Unity
• d) Zero

Answer: Infinity

Question: A copper rod length L and radius r is suspended from the ceilling by one of its ends. What will be elongation of the rod due to its own weight when ρ and Y are the density and Young’s modulus of the copper respectively?

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Answer:

Question: Which of the following substances has the highest elasticity?

• a) Steel
• b) Copper
• c) Rubber
• d) Sponge

Answer: Steel

Question:

• a) 1.6 × 10⁸ Nm^–2
• b) 2.5 × 10¹⁰ Nm^–2
• c) 1.25 × 10¹¹ Nm^–2
• d) None of these

Answer:  1.6 × 10⁸ Nm^–2

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• d) None of these

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Question:  A cube of side 40 mm has its upper face displaced by 0.1 mm by a tangential force of 8 kN. The shearing modulus of cube is

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Question: When a force is applied on a wire of uniform cross-sectional area 3 × 10^–6 m² and length 4 m, the increase in length is 1 mm. Energy stored in it will be (Y = 2 × 10¹¹ N/m²)

• a) 0.075 J
• b) 0.150 J
• c) 0.177 J
• d) 6250 J

Answer: 0.075 J

Question:  If in a wire of Young’s modulus Y, longitudinal strain X is produced then the potential energy stored in its unit volume will be

• a)

  

• b)

  

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• d) None of this

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Question:

• a) 2880 Jm^–3
• b) 1500 Jm^–3
• c) 15750 Jm^–3
• d) 1440 Jm^–3

Answer: 2880 Jm^–3