When a current of 2, A flows in a battery fro | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) Let $E$ be the $emf$ of the battery and $r$ be its internal resistance.When current flows from negative to positive terminal (charging), the termi

Vedclass · Accepted Answer

$13.2$

Vedclass · Answer

(B) Let $E$ be the $emf$ of the battery and $r$ be its internal resistance.When current flows from negative to positive terminal (charging), the terminal potential difference is given by $V = E + Ir$.Given $I = 2\, A$ and $V = 12\, V$, we have:$12 = E + 2r$ ..........$(1)$When current flows in the opposite direction (discharging), the terminal potential difference is given by $V = E - Ir$.Given $I = 3\, A$ and $V = 15\, V$, we have:$15 = E - 3r$ ..........$(2)$Wait, re-evaluating the problem statement: If current flows from negative to positive, it is charging $(V = E + Ir)$. If current flows from positive to negative, it is discharging $(V = E - Ir)$.Let's re-read: "When a current of $2\, A$ flows in a battery from negative to positive terminal, the potential difference across it is $12\, V$." This implies $12 = E + 2r$."If a current of $3\, A$ flows in the opposite direction, the potential difference across the terminals of the battery is $15\, V$." This implies $15 = E - 3r$.Adding $(1)$ and $(2)$ does not yield a simple solution. Let's re-examine the physics: If $V = 12$ when $I=2$ (charging) and $V=15$ when $I=3$ (discharging), this is physically impossible as $V$ should be less than $E$ during discharge. Correct interpretation: The first case is discharging $(V = E - Ir)$ and the second is charging $(V = E + Ir)$.$E - 2r = 12$ ..........$(1)$$E + 3r = 15$ ..........$(2)$Subtracting $(1)$ from $(2)$:$(E + 3r) - (E - 2r) = 15 - 12$$5r = 3 \Rightarrow r = 0.6\, \Omega$Substitute $r$ in $(1)$:$E - 2(0.6) = 12$$E - 1.2 = 12$$E = 13.2\, V$.

Similar Questions

The halide of a metal $MX$ crystallizes in a $ccp$ structure ($NaCl$ type). If all the atoms situated on one of the tetrad axes are removed,what will be the simplest molecular formula of the halide?

If $I$ is the identity matrix of order $2$ and $A = \begin{bmatrix} 1 & 1 \\ 0 & 1 \end{bmatrix}$,then for $n \geq 1$,mathematical induction gives

The equation $\sqrt{3} \sin x + \cos x = 4$ has

$A$ bag $X$ contains $2$ white and $3$ black balls and another bag $Y$ contains $4$ white and $2$ black balls. One bag is selected at random and a ball is drawn from it. Then,the probability for the ball chosen to be white is:

If the function $f$ defined on $\left( \frac{\pi }{6}, \frac{\pi }{3} \right)$ by $f(x) = \begin{cases} \frac{\sqrt{2} \cos x - 1}{\cot x - 1}, & x \neq \frac{\pi}{4} \\ k, & x = \frac{\pi}{4} \end{cases}$ is continuous,then $k$ is equal to

Vedclass Test Series

Exam Paper Generator

Online Exam Module