A) \[10\,\Omega \]
B) \[15\,\Omega \]
C) \[20\,\Omega \]
D) \[25\,\Omega \]
Correct Answer: B
Solution :
Initially, \[\frac{5}{{{l}_{1}}}=\frac{R}{100-{{l}_{1}}}\] (i) Finally, \[\frac{5}{1.6{{l}_{2}}}=\frac{R}{2(100-1.6{{l}_{1}})}\] (ii) \[\Rightarrow \]\[\frac{R}{1.6(100-{{l}_{1}})}=\frac{R}{2(100-1.6{{l}_{2}})}\] \[\Rightarrow \]\[160-1.6{{l}_{1}}=200-3.2\,{{l}_{1}}\] \[\Rightarrow \]\[=1.6{{l}_{1}}=40\] \[\Rightarrow \]\[{{l}_{1}}=25\] From Equation (i), \[\frac{5}{25}=\frac{R}{75}\Rightarrow R=15\,\Omega \]You need to login to perform this action.
You will be redirected in
3 sec