The effective resistance of the network between points $A$ and $B$ is
Easy
Download our app for free and get started
(b)
$R_{\text {net }}=2 r$
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.*
In the figure, the potentiometer wire $AB$ of length $L$ and resistance $9r$ is joined to the cell $D$ of $\mathrm{emf}$ $\varepsilon$ and internal resistance $r$. The cell $C’s$ $\mathrm{emf}$ is $\varepsilon /2$ and its internal resistance is $2r$. The galvanometer $G$ will show no deflection when the length $AJ$ is
Thirteen resistances each of resistance $R\, ohm$ are connected in the circuit as shown in the figure below. The effective resistance between $A$ and $B$ is
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
There are $8$ equal resistances $R$. Two are connected in parallel, such four groups are connected in series, the total resistance of the system will be
An infinite line charge of uniform electric charge density i. lies along the axis of an electrically conducting infinite cylindrical shell of radius $R$. At time $t=0$, the space inside the cylinder is filled with a material of permittivity $\varepsilon$ and electrical conductivity $\sigma$. The electrical conduction in the material follows Ohm's law. Which one of the following graphs best describes the subsequent variation of the magnitude of current censity $j(t)$ at any point in the material?
A heating coil can heat the water of a vessel from $20\,^oC$ to $60\,^oC$ in $30$ minutes. Two such heating coils are put in series and then used to heat the same amount of water through the same temperature range. The time taken now will be ............ $min$ (neglecting thermal capacity of the coils)
In the given circuit, the current flowing through the resistance $20\ \Omega$ is $0.3 \mathrm{~A}$, while the ammeter reads $0.9 \mathrm{~A}$. The value of $\mathrm{R}_1$ is_____________ $\Omega$.