AIIMS 2010
- Exam
- AIIMS
- Year
- 2010
- Subject
- Physics
- Chapter
- Current Electricity
AIIMS 2010 · Physics · Current Electricity
A galvanometer has a current sensitivity of 1 ~mA per division. A...
A galvanometer has a current sensitivity of per division. A variable shunt is connected across the galvanometer and the combination is put in series with a resistance of and cell of internal resistance . It gives a deflection of 5 division for shunt of and 20 division for shunt of . The emf of cell is
Options
- A
- B
- C
- D
Correct answer
A.
Step-by-step solution
Here, and For $S=5 \mathrm{ohm}, I_g=5 \times 10^{-3} \mathrm{~A}$ and for $S=25 \mathrm{ohm}I_g=20 \times 10^{-3} \mathrm{~A}$ Hence, $5 \times 10^{-3}=\frac{E \times 5}{501(G+5)+5 G}$ and $20 \times 10^{-3}=\frac{E \times 25}{501(G+25)+25 G}$ Dividing and solving, G=88.2 \Omega From (i), we get\begin{aligned}E & =10^{-3}[501(88.2+5)+5 \times88.2] \\ & =47.1 \text{ volt } \end{aligned}$$