Q. Two rods of same material and length have their electric resistances in ratio 1 : 2. When both rods are dipped in water, the correct statement will be
A) $A$ has more loss of weight
B) $B$ has more loss of weight
C) Both have same loss of weight
D) Loss of weight will be in the ratio 1 : 2
Explanation
(a) $R = \rho\frac{l}{A} \Rightarrow \frac{R_{1}}{R_{2}} = \frac{A_{2}}{A_{1}}\lbrack\rho,L\ constant\rbrack \Rightarrow \frac{A_{1}}{A_{2}} = \frac{R_{2}}{R_{1}} = 2$
Now, when a body dipped in water, loss of weight
$= V\sigma_{L}g = AL\sigma_{L}g$
So, $\frac{(Loss\ of\ weight)_{1}}{(Loss\ of\ weight)_{2}} = \frac{A_{1}}{A_{2}} = 2$;so $A$ has more loss of weight
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.