The given figure represents an arrangement of potentiometer for the calculation of internal resistance $(r)$ of the unknown battery $(E)$. The balance length is $70.0\, cm$ with the key opened and $60.0\,cm$ with the key closed. $R$ is $132.40 \Omega $. The internal resistance $(r)$ of the unknown cell will be.......$\Omega$ (Given $E_o > E$) :-
Medium
Download our app for free and get startedPlay store
Internal resistance $r=\frac{R\left[l-l^{\prime}\right]}{l^{\prime}}$

where $l=$ balanced length with key open.

$l^{\prime}=$ balanced length with key $K$ closed

$\therefore r=\frac{132.40[70-60]}{60}=\frac{132.40 \times 10}{60}$

$=21.06\, \Omega \approx 22.1\, \Omega$

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
    In the circuit, wire $1$ is of negligible resistance. Then,
    View Solution
  • 2
    By increasing the temperature, the specific resistance of a conductor and a semiconductor
    View Solution
  • 3
    $12$ cells each having the same emf are connected in series and are kept in a closed box. Some of the cells are wrongly connected. This battery is connected in series with an ammeter and two cells identical with each other and also identical with the previous cells. The current is $3\, A$ when the external cells aid this battery and is $2\,A$ when the cells oppose the battery. How many cells in the battery are wrongly connected :-
    View Solution
  • 4
    Consider the following circuit shown below. All the resistors are identical. The ratio of $I / I^{\prime}$ is
    View Solution
  • 5
    All resistances in figure are $1\,\Omega$ each. The value of current ' $I$ ' is $\frac{a}{5}\,A$. The value of $a$ is
    View Solution
  • 6
    The heating coils rating at $220\, volt$ and producing $50\, cal/sec$ heat are available with the resistances $55\,\Omega $ , $110\,\Omega$ ,  $220\,\Omega $ and $440\,\Omega $. The heater of maximum power will be of............. $\Omega$
    View Solution
  • 7
    The effective resistance between the points $A$ and $B$ in the figure is ............. $\Omega$
    View Solution
  • 8
    The figure shows a network of four resistances and three batteries Which of the battery is getting charged.
    View Solution
  • 9
    You are given a resistance wire of length $50\, cm$ and a battery of negligible resistance. In which of the following cases is largest amount of heat generated
    View Solution
  • 10
    Find equivalent resistance between $A$ and $B$
    View Solution