Cells in Series and in Parallel

Two cells of emf  $E_1$  and  $E_2$  and internal resistance  $r_1$  and  $r_2$ , are connected in parallel with each other. Obtain expressions for the equivalent emf and equivalent internal resistance of this parallel combination.

Two cells having the internal resistance $0.2\mathrm{ }\mathrm{\Omega }$ and $0.4\mathrm{ }\mathrm{\Omega }$ are connected in parallel. The voltage across the battery terminals is $1.5 \mathrm{V}$. The emf of first cell is $1.2 \mathrm{V}$, the emf of second cell is (in volt) $E$. Write the value of $\left[E\right],$ where $\left[ \right]$ is the greatest integer function.

To draw a maximum current from a combination of cells, how should the cells be grouped?

$6$ electric cells are connected in series in an electronic device which works at $9$ V potential difference. Emf of on cell is 

To get maximum current through a resistance of $2.5 \mathrm{\Omega }$, one can use $m$ rows of cells, each row having $n$ cells. The internal resistance of each cell is $0.5 \mathrm{\Omega }$. What are the values of $n\mathit{ }\mathit{\text{and }}m\mathit{\text{,}}$ if the total number of cells is $45$?

A student connects four cells, each of emf $1.5 \mathrm{V}$ and internal resistance$0.25 \mathrm{\Omega }$ in series but one cell has its terminals reversed. This battery sends current in a $2 \mathrm{\Omega }$ resistor. The current is :

To get maximum current through a resistance of $2.5\mathrm{\Omega }$, one can use $m$ rows of cells, each row having $n$ cells. The internal resistance of each cell is $0.5\mathrm{\Omega }$. What are the values of $n \& m$, if the total number of cells is $45$?

Two cells with the same emf $\epsilon$ and internal resistance $r_{1 }\& r_2$ are connected in series to an external resistance $R\mathit{.}$ The value of $R$ so that the potential difference across the first cell be zero is:

In the network given below, find the charge on the capacitor (in $\mu \mathrm{C}$) at the steady state.}

In the circuit shown in figure, reading of ammeter will: 

In the arrangement shown in figure, the current through $5\mathrm{\Omega }$ resistor is

A battery of the emf $18 \mathrm{V}$ and internal resistance of $3 \mathrm{\Omega }$ and another battery of emf $10 \mathrm{V}$ and internal resistance of $1 \mathrm{\Omega }$ are connected as shown in figure. Then the voltmeter reading is

${\mathrm{V}}_{\mathrm{A}}-{\mathrm{V}}_{\mathrm{B}}$ is

Assertion: When cells are connected in parallel to the external load, the effective e.m.f increases.

Reason: Because the effective internal resistance of the cells decreases.

Assertion: When cells are connected in parallel to the external load, the effective e.m.f. increases.

Reason: All the cells will be sending the current to the external load in the same direction.

Assertion: When cells are connected in series to the external load the effective e.m.f. increases.

Reason: The cells help each other in sending the current to the external load.

Assertion: When cells are connected in parallel to the external load, the effective e.m.f increases.

Reason: Because the effective internal resistance of the cells decreases.

Assertion: When cells are connected in parallel to the external load, the effective e.m.f. increases.

Reason: All the cells will be sending the current to the external load in the same direction.

Assertion: When cells are connected in series to the external load the effective e.m.f. increases.

Reason: The cells help each other in sending the current to the external load.

Find the net $\mathrm{e}\mathrm{m}\mathrm{f}$ of the three batteries shown in figure -