Question:
Two cells \(A\) and \(B\) are connected in the secondary circuit of a potentiometer one at a time and the balancing lengths are respectively \(360\ \text{cm}\) and \(420\ \text{cm}\). If emf of \(A\) is \(2.4\ \text{V}\), the emf of the second cell \(B\) is
Two cells \(A\) and \(B\) are connected in the secondary circuit of a potentiometer one at a time and the balancing lengths are respectively \(360\ \text{cm}\) and \(420\ \text{cm}\). If emf of \(A\) is \(2.4\ \text{V}\), the emf of the second cell \(B\) is
Show Hint
In a potentiometer comparison of emfs,
\[
\frac{E_1}{E_2}=\frac{l_1}{l_2}.
\]
The cell with the greater balancing length has the greater emf.
Updated On: Jun 26, 2026
- \(2.8\ \text{V}\)
- \(3.2\ \text{V}\)
- \(3.0\ \text{V}\)
- \(2.6\ \text{V}\)
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Use the potentiometer principle.
In a potentiometer, the emf of a cell is directly proportional to the balancing length.
Therefore, \[ \frac{E_A}{E_B}=\frac{l_A}{l_B}. \]
Step 2: Substitute the given values.
Given, \[ E_A=2.4\ \text{V}, \] \[ l_A=360\ \text{cm}, \] and \[ l_B=420\ \text{cm}. \] Thus, \[ \frac{2.4}{E_B}=\frac{360}{420}. \]
Step 3: Solve for \(E_B\).
\[ E_B=2.4\times \frac{420}{360}. \] \[ E_B=2.4\times \frac{7}{6}. \] \[ E_B=2.8\ \text{V}. \]
Step 4: Final conclusion.
Therefore, the emf of the second cell \(B\) is \[ \boxed{2.8\ \text{V}} \] Hence, the correct option is \[ \boxed{(1)} \]
In a potentiometer, the emf of a cell is directly proportional to the balancing length.
Therefore, \[ \frac{E_A}{E_B}=\frac{l_A}{l_B}. \]
Step 2: Substitute the given values.
Given, \[ E_A=2.4\ \text{V}, \] \[ l_A=360\ \text{cm}, \] and \[ l_B=420\ \text{cm}. \] Thus, \[ \frac{2.4}{E_B}=\frac{360}{420}. \]
Step 3: Solve for \(E_B\).
\[ E_B=2.4\times \frac{420}{360}. \] \[ E_B=2.4\times \frac{7}{6}. \] \[ E_B=2.8\ \text{V}. \]
Step 4: Final conclusion.
Therefore, the emf of the second cell \(B\) is \[ \boxed{2.8\ \text{V}} \] Hence, the correct option is \[ \boxed{(1)} \]
Was this answer helpful?
0
0
Top AP EAPCET Physics Questions
- A body is projected from the ground at an angle of $\tan^{-1} \left( \frac{8}{7}\right)$ with the horizontal. The ratio of the maximum height attained by it to its range is
- A lens forms real and virtual images of an object, when the object is at $u_{1}$ and $u_{2}$ distances respectively. If the size of the virtual image is double that of the real image, then the focal length of the lens is (take, the magnification of the real image as $m$ )
- Two spheres $P$ and $Q$, each of mass $200\, g$ are attached to a string of length one metre as shown in the figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant angular speed. The ratio of the tension in the string between $P$ and $Q$ to that of between $P$ and $O$ is $(P$ is at mid-point of the line joining $O$ and $Q$ )
- The radii of the two columns in a U - tube are r1 and r2. When a liquid of density p (angle of contact is $ 0{}^\circ $ ) is filled in it, the level difference of the liquid in the two arms is h. The surface tension of the liquid is: (g = acceleration due to gravity)
- A rigid metallic sphere is spinning around its own axis in the absence of external torque. If the temperature is raised, its volume increases by $9 \%$. The change in its angular speed is
View More Questions
Top AP EAPCET Electrical Circuits Questions
- A uniform metal wire carries a current of 2 A when an ideal cell of 3.4 V is connected across it. The wire has mass \( 8.92 \times 10^{-3} \, \text{kg} \), density \( 8.92 \times 10^3 \, \text{kg/m}^3 \) and resistivity \( 1.7 \times 10^{-8} \, \Omega \text{m} \). Then the length of the wire is
In the given circuit, the potential difference across the plates of the capacitor \( C \) in steady state is
A part of a circuit is shown in the figure. The ratio of the potential differences between the points A and C, and the points D and E is.
- A DC supply of \(160\,V\) is used to charge a battery of EMF \(10\,V\) and internal resistance \(1\,\Omega\) by connecting a series resistance of \(24\,\Omega\). The terminal voltage of the battery during charging is:
- In a series resonant LCR circuit, for the power dissipated to become half of the maximum power dissipated, the current amplitude is
View More Questions
Top AP EAPCET Questions
- A body is projected from the ground at an angle of $\tan^{-1} \left( \frac{8}{7}\right)$ with the horizontal. The ratio of the maximum height attained by it to its range is
- The four quantum numbers of the valence electron of potassium are :
- A lens forms real and virtual images of an object, when the object is at $u_{1}$ and $u_{2}$ distances respectively. If the size of the virtual image is double that of the real image, then the focal length of the lens is (take, the magnification of the real image as $m$ )
- Two spheres $P$ and $Q$, each of mass $200\, g$ are attached to a string of length one metre as shown in the figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant angular speed. The ratio of the tension in the string between $P$ and $Q$ to that of between $P$ and $O$ is $(P$ is at mid-point of the line joining $O$ and $Q$ )
- The volume of $0.02\, M$ acidified permanganate solution required for complete reaction of $60\, mL$ of $0.01\, MI^{-}$ ion solution to form $I_2$ in $mL$ is
View More Questions