Question:
A battery with a \(12\,\text{V}\) emf has an initial charge of \(80\,\text{A h}\). If the potential across the terminals stays constant until battery is completely discharged, then this battery can deliver energy at the rate of \(120\,\text{W}\) for a time:
A battery with a \(12\,\text{V}\) emf has an initial charge of \(80\,\text{A h}\). If the potential across the terminals stays constant until battery is completely discharged, then this battery can deliver energy at the rate of \(120\,\text{W}\) for a time:
Show Hint
Battery capacity in ampere-hour is given by:
\[
\text{Capacity}=I\times t.
\]
First calculate current using
\[
P=VI,
\]
then determine the operating time.
Updated On: Jun 24, 2026
- \(16\,\text{h}\)
- \(8\,\text{h}\)
- \(4\,\text{h}\)
- \(5\,\text{h}\)
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Step 1: Write the given battery capacity.
Battery capacity: \[ 80\,\text{A h} \] Voltage: \[ V=12\,\text{V} \] Power supplied: \[ P=120\,\text{W} \]
Step 2: Find the current supplied by the battery.
Using \[ P=VI \] \[ 120=12\times I \] \[ I=10\,\text{A} \]
Step 3: Use battery capacity relation.
Battery capacity is \[ \text{Capacity}=I\times t \] Thus, \[ 80=10\times t \] \[ t=8\,\text{h} \]
Step 4: Final conclusion.
Hence, the battery can supply power for \[ \boxed{8\,\text{h}} \]
Battery capacity: \[ 80\,\text{A h} \] Voltage: \[ V=12\,\text{V} \] Power supplied: \[ P=120\,\text{W} \]
Step 2: Find the current supplied by the battery.
Using \[ P=VI \] \[ 120=12\times I \] \[ I=10\,\text{A} \]
Step 3: Use battery capacity relation.
Battery capacity is \[ \text{Capacity}=I\times t \] Thus, \[ 80=10\times t \] \[ t=8\,\text{h} \]
Step 4: Final conclusion.
Hence, the battery can supply power for \[ \boxed{8\,\text{h}} \]
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 Current electricity Questions
- A block has dimensions 1 cm, 2 cm, and 3 cm. The ratio of the maximum resistance to minimum resistance between any pair of opposite faces of the block is:
A current of \(6A\) enters one corner \(P\) of an equilateral triangle \(PQR\) having three wires of resistance \(2 \Omega\) each and leaves by the corner \(R\) as shown in figure. Then the currents \(I_1\) and \(I_2\) are respectively
The value of shunt resistance that allows only 10% of the main current through the galvanometer of resistance \( 99 \Omega \) is:
In the given circuit, the potential difference between B and D is zero. Then the value of the current I is
In the given circuit, if the cell delivers maximum power to the circuit, then value of $R$ 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