A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of $2.0\,V$ and a negligible internal resistance. The potentiometer wire itself is $4\,m$ long. When the resistance $R,$ connected across the given cell, has values of $(i)$ infinity $(ii)$ $9.5\,\Omega$ the balancing lengths on the potentiometer wire are found to be $3\,m$ and $2.85\,m,$ respectively. The value of internal resistance of the cell is ............... $\Omega$
AIPMT 2014, Medium
Download our app for free and get started
The internal resistance of the cell is
$r=\left(\frac{l_{1}}{l_{2}}-1\right) R$
Here, $l_{1}=3\, \mathrm{m}, l_{2}=2.85\, \mathrm{m}, R=9.5\, \Omega$
$\therefore \quad r=\left(\frac{3}{2.85}-1\right)(9.5 \,\Omega)=\frac{0.15}{2.85} \times 9.5\, \Omega=0.5\, \Omega$
Download our appand 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
- 1The current between $B$ and $D$ in the given figure is .............. $amp$View Solution
- 2The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be..... $\%$.View Solution
- 3A uniform heating wire of resistance $36\, \Omega$ is connected across a potential difference of $240\, {V}$ The wire is then cut into half and potential difference of $240\, {V}$ is applied across each half separately. The ratio of power dissipation in first case to the total power dissipation in the second case would be $1: {x}$, where ${x}$ is........... .View Solution
- 4In the circuit shown, the current through the $4\,\Omega $ resistor is $1\, amp$ when the points $P$ and $M$ are connected to a d.c. voltage source. The potential difference between the points $M$ and $N$ is ............... $volt$View Solution
- 5In a conductor $4$ coulombs of charge flows for $2$ seconds. The value of electric current will beView Solution
- 6Two cells of same emf but different internal resistances $I_{1}$ and $I_{2}$ are connected in series with a resistance $R$. The value of resistance $R$, for which the potential difference across second cell is zero, isView Solution
- 7In the following star circuit diagram (figure), the equivalent resistance between the points $A$ and $H$ will be ..............$r$View Solution
- 8View SolutionWhich of the following statement is correct
- 9A battery having $e.m.f.$ $5\,\,V$ and internal resistance $0.5$ $\Omega$ is connected with a resistance of $4.5 \,\Omega$ then the voltage at the terminals of battery is ............. $V$View Solution
- 10If ${R_1}$ and ${R_2}$ are respectively the filament resistances of a $200$ $watt$ bulb and $100$ $watt$ bulb designed to operate on the same voltage, thenView Solution