Physics Elasticity Question 71
Question: Wires A and B are made from the same material. A has twice the diameter and three times the length of B. If the elastic limits are not reached, when each is stretched by the same tension, the ratio of energy stored in A to that in B is
[Kerala PMT 2004]
Options:
A) 2 : 3
B) 3 : 4
C) 3 : 2
D) 6 : 1
Show Answer
Answer:
Correct Answer: B
Solution:
$ U=\frac{1}{2}Fl=\frac{F^{2}L}{2AY} $ .$ U\propto \frac{L}{r^{2}} $ (F and Y are constant) $ \frac{U _{A}}{U _{B}}=\left( \frac{L _{A}}{L _{B}} \right)\times {{\left( \frac{r _{A}}{r _{B}} \right)}^{2}} $ = $ (3)\times {{\left( \frac{1}{2} \right)}^{2}}=\frac{3}{4} $
BETA
