Two cells of $emfs$ $E_1$ and $E_2$ and internal resistances $r_1$ and $r_2$ are connected in parallel. The $emf$ and internal resistance of the equivalent source is
  • A${E_1}\, + \,{E_2}$  and  $\frac{{{r_1}{r_2}}}{{{r_1} + {r_2}}}$
  • B${E_1}\, - \,{E_2}$  and  $r_1\, +\, r_2$
  • C$\frac{{{E_1}{r_2}\, + \,\,{E_2}{r_1}}}{{{r_1} + {r_2}}}$  and  $\frac{{{r_1}{r_2}}}{{{r_1} + {r_2}}}$
  • D$\frac{{{E_1}{r_2}\, + \,\,{E_2}{r_1}}}{{{r_1} + {r_2}}}$  and  $r_1\, +\, r_2$
Medium
art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    Wheatstone bridge principle is used to measure the specific resistance $\left(S_1\right)$ of given wire, having length $L$, radius $r$. If $X$ is the resistance of wire, then specific resistance is: $S_1=X\left(\frac{\pi r^2}{L}\right)$. If the length of the wire gets doubled then the value of specific resistance will be :
    View Solution
  • 2
    A resistor ${R_1}$ dissipates the power $P$ when connected to a certain generator. If the resistor ${R_2}$ is put in series with ${R_1}$, the power dissipated by ${R_1}$
    View Solution
  • 3
    When the current $i$ is flowing through a conductor, the drift velocity is $v$. If $2i$ current is flowed through the same metal but having double the area of cross-section, then the drift velocity will be
    View Solution
  • 4
    At room temperature $\left(27^{\circ} \mathrm{C}\right)$, the resistance of a heating element is $50 \Omega$. The temperature coefficient of the material is $2.4 \times 10^{-4}{ }^{\circ} \mathrm{C}^1$. The temperature of the element, when its resistance is $62 \Omega$, is $\qquad$ ${ }^{\circ} \mathrm{C}$.
    View Solution
  • 5
    Find potential at point $C$ and $D$
    View Solution
  • 6
    Two electric bulbs have tungsten filament of same length. If one of them gives $60\ W$ and the other $100\ W$ , then
    View Solution
  • 7
    A $25\, watt$, $220\, volt$ bulb and a $100\, watt$, $220\, volt$ bulb are connected in series across a $220\, volt$ lines. Which electric bulb will glow more brightly
    View Solution
  • 8
    $A$ Wheatstone's bridge is balanced with a resistance of $625\, \Omega$ in the third arm, where $P, Q$ and $S$ are in the $1^{st}, 2^{nd}$ and $4^{th}$ arm respectively. If $P$ and $Q$ are interchanged, the resistance in the third arm has to be increased by $51\,\Omega$ to secure balance. The unknown resistance in the fourth arm is ............. $\Omega$
    View Solution
  • 9
    Two wires of same length and thickness having specific resistances $6\, \Omega \,cm$ and $3 \,\Omega\, cm$ respectively are connected in parallel. The effective resistivity is $\rho\, \Omega \,cm$. The value of $\rho$ to the nearest integer, is ..... .
    View Solution
  • 10
    Electric room radiator which operates at $225\, volts$ has resistance of $50\, ohms$. Power of the radiator is approximately ............... $W$
    View Solution