Physics Elasticity Question 144
Question: A load W produces an extension of 1mm in a thread of radius r. Now if the load is made 4W and radius is made 2r all other things remaining same, the extension will become
[RPET 2000]
Options:
A) 4 mm
B) 16 mm
C) 1 mm
D) 0.25 mm
Show Answer
Answer:
Correct Answer: C
Solution:
$ l=\frac{FL}{AY}\
Therefore l\propto \frac{F}{r^{2}} $
$ \frac{l _{1}}{l _{2}}=\frac{F _{2}}{F _{1}}{{\left( \frac{r _{1}}{r _{2}} \right)}^{2}}=(4)\times {{\left( \frac{1}{2} \right)}^{2}}=1 $ $ l _{2}=l _{1}=1mm $
BETA
