Two cells of $e.m.f.$ $s\, E_1$ and $E_2$ and of negligible internal resistances are connected with two variable resistors as shown in Fig. When the galvanometer shows no deflection, the values of the resistances are $P$ and $Q$. What is the value of the ratio $E_2/E_1$ ?
  • A$\frac{P}{Q}$
  • B$\frac{P}{{P + Q}}$
  • C$\frac{Q}{{P + Q}}$
  • D$\frac{{P + Q}}{P}$
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
    The current through a wire depends on time as $i = (2+3t)\, mA$. The charge crossing through a section of the wire in $1\, min$ is .............. $\mathrm{C}$
    View Solution
  • 2
    Consider a block of conducting material ofresistivity '$\rho$' shown in the figure. Current '$I$' enters at '$A$' and leaves from '$D$'. We apply superp osition principle to find voltage '$\Delta  V$ ' developed between '$B$' and '$C$'. The calculation is done in the following steps:
    $(i)$ Take current '$I$' entering from '$A$' and assume it to spread over a hemispherical surface in the block.
    $(ii)$ Calculatefield $E(r)$ at distance '$r$' from $A$ by using Ohm's law $E = \rho  j$, where j is the current per unit area at '$r$'.
    (iii) From the '$r$' dependence of $E(r)$, obtain the potential $V(r)$ at $r$.
    (iv) Repeat $(i), (ii)$ and $(iii)$ for current '$I$' leaving '$D$' and superpose results for '$A$' and '$D$'.

    $\Delta V$ measured between $B$ and $C$ is

    View Solution
  • 3
    The potential difference $(V_A - V_B)$ between the points $A$ and $B$ in the given figure is ............ $V$
    View Solution
  • 4
    A battery of $e.m.f.$ $E$ and internal resistance $r$ is connected to a variable resistor $R$ as shown here. Which one of the following is true
    View Solution
  • 5
    In the given potentiometer circuit, the resistance of the potentiometer wire $AB$ is $R_0$. $C$ is a cell of internal resistance $r$. The galvanometer $G$ does not give zero deflection for any position of the jockey $J$. Which of the following cannot be a reason for this?
    View Solution
  • 6
    The resistance of a wire is $5\,ohm$  at $50\,^o C$ and $6\,ohm $ at $100\,^o C$. The resistance of the wire at $0\,^o C$ will be .............. $\Omega$
    View Solution
  • 7
    The resistance of a wire is $20\, ohms$. It is so stretched that the length becomes three times, then the new resistance of the wire will be ............. $ohms$
    View Solution
  • 8
    In the circuit shown below, The reading of the voltmeter $V$ is ...........
    View Solution
  • 9
    Which is a wrong statement
    View Solution
  • 10
    In the circuit shown below, the key is pressed at time $t=0$. Which of the following statement(s) is(are) true?

    ($A$) The voltmeter displays $-5 \mathrm{~V}$ as soon as the key is pressed, znd displays $+5 \mathrm{~V}$ after a long time

    ($B$) The voltmeter will display $0 \mathrm{~V}$ at time $t=\ln 2$ seconds

    ($C$) The current in the ammeter becomes $1 / e$ of the initial value after $1$ second

    ($D$) The current in the ammeter becomes zero after a long time

    View Solution