In a potentiometer experiment the balancing with a cell is at length $240\,cm$ . On shunting the cell with a resistance of $2\,\Omega $ , the balancing length becomes $120\, cm$ . The internal resistance of the cell is ................... $\Omega$
A$4$
B$2$
C$1$
D$0.5$
Medium
Download our app for free and get started
B$2$
b Internal resistance of a cell $r$ is given by
$r=R\left[\frac{l_{1}}{l_{2}}-1\right]$
$\Rightarrow r=2\left[\frac{240}{120}-1\right]$
$\Rightarrow r=2 \times 1=2 \Omega$
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.*
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
Two bulbs consume same power when operated at $200\, V$ and $300\, V$ respectively. When these bulbs are connected in series across a $D.C$. source of $500\, V$, then
Three identical bulbs $B_1, B_2$ and $B_3$ are connected to the mains as shown in figure. If $B_3$ is disconnected from the circuit by opening switch $S$, then incandescence of bulb $B_1$ will
Two cities are $150\,\, km$ apart. Electric power is sent from one city to another city through copper wires. The fall of potential per $km$ is $8\,\, volt$ and the average resistance per km is $0.5 \,\,\Omega .$ The power loss in the wire is
A $6\,\,V$ battery is connected to the terminals of a $3\, m$ long uniform wire having resistance $100\,\Omega $. The difference in potential between two points on the wire separated by a distance of $50\, cm$ will be ............. $V$
A wire of resistance $20 \Omega$ is divided into $10$ equal parts. A combination of two parts are connected in parallel and so on. Now resulting pairs of parallel combination are connected in series. The equivalent resistance of final combination is_______.0$\Omega$.