JEE PYQ: Properties Of Matter Question 6
Question 6 - 2021 (26 Feb 2021 Shift 2)
The length of metallic wire is $l_1$ when tension in it is $T_1$. It is $l_2$ when the tension is $T_2$. The original length of the wire will be:
(1) $\frac{l_1 l_2}{2}$
(2) $\frac{T_2 l_1 - T_1 l_2}{T_2 - T_1}$
(3) $\frac{T_2 l_1 + T_1 l_2}{T_2 + T_1}$
(4) $\frac{T_1 l_1 - T_2 l_2}{T_2 - T_1}$
Show Answer
Answer: (4)
Solution
From Young’s modulus: $\frac{T_1}{A} = \frac{Y(l_1 - l)}{l}$ and $\frac{T_2}{A} = \frac{Y(l_2 - l)}{l}$
$T_2 l_1 - T_2 l = T_1 l_2 - T_1 l \Rightarrow l = \frac{T_2 l_1 - T_1 l_2}{T_2 - T_1}$
BETA
