Mixed Combination of Cells

Q. $N$ cells each of e.m.f. $E$ & internal resistance $r$ are grouped into sets of $K$ cells connected in series. The $\left(\frac{N}{K}\right)$ sets are connected in parallel to a load of resistance $R$, then:

1. Maximum power is delivered to the load if $K=\sqrt{\frac{NR}{r}}$
2. Maximum power is delivered to the load if $K=\sqrt{\frac{r}{NR}}$
3. Maximum power delivered to the load is $\frac{N{E}^2}{4r}$
4. Maximum power delivered to the load is $\frac{E^2}{4Nr}$

Q.

What is the potential difference between points B and D in the given circuit.

1. 1/13 A

2. 1/14 A

3. 1/15 A

4. None of the above

Q. To get maximum current in a resistance of $3\Omega$ one can use n rows of m cells connected in parallel. If the total no. of cells is 24 and the internal resistance of a cell is$0.5\Omega$ then

1. m = 12, n = 2
2. m = 8, n = 4
3. m = 2, n = 12
4. m = 6, n = 4

Q. Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in 100 rows, each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of 0.15 V and internal resistance of 0.25$\Omega$. The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500 ohm, the current an eel can produce in water is about

1. 1.5 A
2. 3.0 A
3. 15 A
4. 30 A

Q. A network consisting of three resistors, three batteries, and a capacitor is shown in the figure

$\begin{array}{ccc}& \text{Column I}& \text{Column II}\\ \left(A\right)& \text{Current in branch EB is}& \text{(P)}10\mu C\\ \left(B\right)& \text{Current in branch CB is}& \text{(Q)}0.5\mu C\\ \left(C\right)& \text{Current in branch ED is}& \text{(R)}1.5\mu C\\ \left(D\right)& \text{Charge on capacitor is}& \text{(S)}5\mu C\\ & & \text{(T)}7.5\mu C\end{array}$
Which of the following option has the correct combination considering column - I and Column - II.

1. $A\to S$
2. $B\to R$
3. $C\to Q$
4. $D\to T$

Q. Q42. (a) How will you join three resistors of resistance 4 $\Omega$, 6 $\Omega$ and 12 $\Omega$ to get an equivalent resistance of 8$\Omega$.
(b) What would be the highest and the lowest equivalent resistance possible by joining these resistors.