Consider four circuits shown in the figure below. In which circuit power dissipated is greatest (Neglect the internal resistance of the power supply)

(1)

(2)

(3)

(4)

In the circuit, the reading of the ammeter is (assume internal resistance of the battery be zero) :

1. $\frac{40}{29}A$

2. $\frac{10}{9}A$

3. $\frac{5}{3}A$

4. 2 A

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 Ω 

The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500 Ω, the current an eel can produce in water is about

(1) 1.5 A

(2) 3.0 A

(3) 15 A

(4) 30 A

A battery is charged at a potential of 15 V for 8 hours when the current flowing is 10 A. The battery on discharge supplies a current of 5 A for 15 hours. The mean terminal voltage during discharge is 14 V. The "Watt-hour" efficiency of the battery is :

(1) 82.5%

(2) 80 %

(3) 90%

(4) 87.5%

A capacitor is connected to a cell of emf E having some internal resistance r. The potential difference in steady state across the 

(1) Cell is < E

(2) Cell is E

(3) Capacitor is > E

(4) Capacitor is < E

The maximum power drawn out of the cell from a source is given by (where r is internal resistance)  

(1) $E^2/2r$

(2) $E^2/4r$

(3) $E^2/r$

(4) $E^2/3r$

Find out the value of current through 2Ω resistance for the given circuit 

(1) 5 A

(2) 2 A

(3) Zero

(4) 4 A

Two sources of equal emf are connected to an external resistance R. The internal resistances of the two sources are R₁ and $R_2(R_2>R_1)$. If the potential difference across the source having internal resistance R₂ is zero, then 

(1) $R=R_1{R}_2/(R_1+R_2)$

(2) $R=R_1{R}_2/(R_2-R_1)$

(3) $R=R_2\times (R_1+R_2)/(R_2-R_1)$

(4) $R=R_2-R_1$

The magnitude of i in ampere unit is 

(1) 0.1

(2) 0.3

(3) 0.6

(4) None of these

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

(1) Series

(2) Parallel

(3) Mixed

(4) Depends upon the relative values of external and internal resistance