JEE PYQ: Properties Of Matter Question 12
Question 12 - 2019 (08 Apr 2019 Shift 2)
Young’s moduli of two wires A and B are in the ratio 7 : 4. Wire A is 2 m long and has radius R. Wire B is 1.5 m long and has radius 2 mm. If the two wires stretch by the same length for a given load, then the value of R is close to:
(1) 1.5 mm
(2) 1.9 mm
(3) 1.7 mm
(4) 1.3 mm
Show Answer
Answer: (3)
Solution
$\Delta_1 = \Delta_2 \Rightarrow \frac{Fl_1}{\pi r_1^2 Y_1} = \frac{Fl_2}{\pi r_2^2 Y_2}$
$\frac{2}{R^2 \times 7} = \frac{1.5}{2^2 \times 4} \Rightarrow R = 1.75$ mm
BETA
