Current Electricity Ques 90 — JEE PYQ Chapterwise

Answer:

Correct Answer: 90.$(5)$

Solution:

Formula:

Ammeter:

$i _g(G+4990)=V$

$ \begin{aligned} & \Rightarrow \quad \frac{6}{1000}(G+4990)=30 \\ & \Rightarrow \quad G+4990=\frac{30000}{6}=5000 \\ & \Rightarrow \quad G=10 \Omega \\ & \quad \quad V _{a b}=V _{c d} \\ & \Rightarrow \quad i _g G=\left(1.5-i _g\right) S \\ & \Rightarrow \quad \frac{6}{1000} \times 10=1.5-\frac{6}{1000} S \\ & \Rightarrow \quad S=\frac{60}{1494}=\frac{2 n}{249} \\ & \Rightarrow \quad n=\frac{249 \times 30}{1494}=\frac{2490}{498}=5 \end{aligned} $