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: A

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: A

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: A

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: A

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: A

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: A

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: A

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: A

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 : 2
(d) None of these

Answer: A

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: A

Question. The Bulk modulus for an incompressible liquid is
(a) Infinity
(b) Between 0 and 1
(c) Unity
(d) Zero

Answer: A

Question. Which of the following substances has the highest elasticity?
(a) Steel
(b) Copper
(c) Rubber
(d) Sponge

Answer: A

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: A