Question:
A moving coil galvanometer of resistance \(100\,\Omega\) shows a full scale deflection for a current of \(1\,\text{mA}\). The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of \(5\,\text{mA}\), is ________ \(\Omega\).
A moving coil galvanometer of resistance \(100\,\Omega\) shows a full scale deflection for a current of \(1\,\text{mA}\). The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of \(5\,\text{mA}\), is ________ \(\Omega\).
Show Hint
To convert a galvanometer into an ammeter, always connect a low resistance shunt in parallel.
Updated On: Feb 5, 2026
- 25
- 2.5
- 10
- 0.5
Hide Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Identify given quantities.
Galvanometer resistance, \(G = 100\,\Omega\)
Galvanometer full scale current, \(I_g = 1\,\text{mA}\)
Required full scale current, \(I = 5\,\text{mA}\)
Step 2: Use formula for shunt resistance.
\[ S = \frac{G I_g}{I - I_g} \]
Step 3: Substitute values.
\[ S = \frac{100 \times 1}{5 - 1} = \frac{100}{4} = 25\,\Omega \]
Galvanometer resistance, \(G = 100\,\Omega\)
Galvanometer full scale current, \(I_g = 1\,\text{mA}\)
Required full scale current, \(I = 5\,\text{mA}\)
Step 2: Use formula for shunt resistance.
\[ S = \frac{G I_g}{I - I_g} \]
Step 3: Substitute values.
\[ S = \frac{100 \times 1}{5 - 1} = \frac{100}{4} = 25\,\Omega \]
Was this answer helpful?
0
0
Top Questions on Current electricity
- The pulley shown in figure is made using a thin rim and two rods of length equal to diameter of the rim. The rim and each rod have a mass of $M$. Two blocks of mass of $M$ and $m$ are attached to two ends of a light string passing over the pulley, which is hinged to rotate freely in vertical plane about its center. The magnitudes of the acceleration experienced by the blocks is _________ (assume no slipping of string on pulley).
- JEE Main - 2026
- Physics
- Current electricity
- In a meter bridge experiment to determine the value of unknown resistance, first the resistances \(2\,\Omega\) and \(3\,\Omega\) are connected in the left and right gaps of the bridge and the null point is obtained at a distance \(l\) cm from the left end. Now, when an unknown resistance \(x\,\Omega\) is connected in parallel to \(3\,\Omega\), the null point is shifted by \(10\,\text{cm}\) to the right. The value of \(x\) is ________ \(\Omega\).
- JEE Main - 2026
- Physics
- Current electricity
- The reading of the ammeter (\(A\)) in steady state in the following circuit (assuming negligible internal resistance of the ammeter) is ________ A.
- JEE Main - 2026
- Physics
- Current electricity
The heat generated in 1 minute between points A and B in the given circuit, when a battery of 9 V with internal resistance of 1 \(\Omega\) is connected across these points is ______ J.
- JEE Main - 2026
- Physics
- Current electricity
A Wheatstone bridge is initially at room temperature and all arms of the bridge have same value of resistances \[ (R_1=R_2=R_3=R_4). \] When \(R_3\) resistance is heated, its resistance value increases by \(10%\). The potential difference \((V_a-V_b)\) after \(R_3\) is heated is _______ V.
- JEE Main - 2026
- Physics
- Current electricity
View More Questions
Questions Asked in JEE Main exam
- Paratrooper jumps... opens parachute after 2s... initial height is ___ m.
- JEE Main - 2026
- Kinematics
- Let \( y = x \) be the equation of a chord of the circle \( C_1 \) (in the closed half-plane \( x \ge 0 \)) of diameter 10 passing through the origin. Let \( C_2 \) be another circle described on the given chord as diameter. If the equation of the chord of the circle \( C_2 \), which passes through the point \( (2, 3) \) and is farthest from the center of \( C_2 \), is \( x + ay + b = 0 \), then \( b \) is equal to:
- JEE Main - 2026
- Coordinate Geometry
- For given vectors \( \vec{a} = -\hat{i} + \hat{j} + 2\hat{k} \) and \( \vec{b} = 2\hat{i} - \hat{j} + \hat{k} \) where \( \vec{c} = \vec{a} \times \vec{b} \) and \( \vec{d} = \vec{c} \times \vec{b} \). Then the value of \( (\vec{a}-\vec{b}) \cdot \vec{d} \) is:
- JEE Main - 2026
- Vector Algebra
- Given that \[ \vec a=2\hat i+\hat j-\hat k,\quad \vec b=\hat i+\hat j,\quad \vec c=\vec a\times\vec b, \] \[ |\vec d\times\vec c|=3,\quad \vec d\cdot\vec c=\frac{\pi}{4},\quad |\vec a-\vec d|=\sqrt{11}, \] find $\vec a\cdot\vec d$.
- JEE Main - 2026
- Vector Algebra
- If three vectors are given as shown. If the angle between vectors \( \vec{p} \) and \( \vec{q} \) is \( \theta \), where \[ \cos \theta = \frac{1}{\sqrt{3}}, \quad |\vec{p}| = 2\sqrt{3}, \quad |\vec{q}| = 2, \] then find the value of \[ \left| \vec{p} \times (\vec{q} - 3\vec{r}) \right|^{2} - 3|\vec{r}|^{2}. \]
- JEE Main - 2026
- Vector Algebra
View More Questions