Two sources of equal $emf$ are connected to an external resistance $R$. The internal resistances of the two sources are $R_1$ and $R_2$ $(R_2 > R_1)$. If the potential difference across the source having internal resistance $R_2$ is zero,then:

  • A
    $R = R_1 R_2 / (R_1 + R_2)$
  • B
    $R = R_1 R_2 / (R_2 - R_1)$
  • C
    $R = R_2 \times (R_1 + R_2) / (R_2 - R_1)$
  • D
    $R = R_2 - R_1$

Explore More

Similar Questions

Match the points on the curve $2y^2 = x + 1$ with the slopes of the normals at those points and choose the correct answer.
PointSlope of the normal
$A. (7, 2)$$1. -4\sqrt{2}$
$B. (0, 1/\sqrt{2})$$2. -8$
$C. (1, -1)$$3. 4$
$D. (3, \sqrt{2})$$4. 0$
$5. -2\sqrt{2}$

Consider the fourteen lines in the plane given by $y=x+r$ and $y=-x+r$,where $r \in \{0, 1, 2, 3, 4, 5, 6\}$. The number of squares formed by these lines,whose sides are of length $\sqrt{2}$,is:

What will be the ratio of de-Broglie wavelengths of a proton and an $\alpha$-particle of the same energy?

Two bodies of masses $m$ and $4m$ are placed at a distance $r$. The gravitational potential at a point on the line joining them where the gravitational field is zero is

Match the items given in Column $I$ with those in Column $II$ and select the correct option given below:
Column $I$ Column $II$
$(a)$ Tidal volume $(i)$ $2500 - 3000 \ mL$
$(b)$ Inspiratory Reserve volume $(ii)$ $1100 - 1200 \ mL$
$(c)$ Expiratory Reserve volume $(iii)$ $500 - 550 \ mL$
$(d)$ Residual volume $(iv)$ $1000 - 1100 \ mL$

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo