Related InterviewSolutions

• A wire elongates by l mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be (in mm) (1) zero (2) l/2 (3) l (4) 2l 
• The property of metals whereby they could be drawn into thin wires beyond their elastic limit without breaking is  (1) Ductility (2) Malleability (3) Elasticity (4) Hardness 
• The possible value of Poisson’s ratio is (1) 0.9 (2) 0.8 (3) 0.4 (4) 1 
• A heavy mass is attached to a thin wire and is whirled in a vertical circle. The wire is most likely to break (1) When the mass is at the lowest point  (2) When mass is at the highest point  (3) When wire is horizontal  (4) When mass is at an angle of cos-1 (1/√2) from upward vertical 
• The breaking stress of a wire depends on  (1) Material of a wire (2) Shape of cross section  (3) Length of the wire (4) Radius of the wire
• Steel is preferred for making springs over copper because  (1) Young's modulus of steel is more than that of copper ( 2) Steel is cheaper  (3) Young's modulus of copper is more ( 4) Steel is less likely to be oxidized
• Steel is preferred for making springs over copper because  (1) Young's modulus of steel is more than that of copper  (2) Steel is cheaper  (3) Young's modulus of copper is more  (4) Steel is less likely to be oxidized 
• The following four wires are made of the same material subjected to same force arrange them with their elongations in ascending order(a) l = 50cm and r = 0.5mm (b) l = 100cm and r = 1mm  (c) l = 200cm and r = 2mm (d) l = 300cm and r = 3mm  (1) a, b, c, d (2) c, d, a, b (3) a, d, c, b (4) d, c, b, a 
• (A): Identical springs of steel and copper are equally stretched. More work will be done on the steel spring.  (R): Steel is more elastic than copper. (1) Both (A) and (R) are true and (R) is the correct explanation of (A) (2) Both (A) and (R) are true and (R) is not the correct explanation of (A) (3) (A) is true but (R) is false (4) (A) is false but (R) is true 
• A copper wire of negligible mass, length 1 m and cross-sectional area 10–6 m2 is kept on a smooth horizontal table with one end fixed. A ball of mass 1 kg is attached to the other end. The wire and the ball are rotating with an angular velocity of 20 rad/s. If the elongation in the wire is 10–3 m, obtain the Young’s modulus of copper. If on increasing the angular velocity to 100 rad/s, the wire breaks down, obtain the breaking stress.