The resultant resistance value of n resistors, each of r ohms and connected in series is x. When those n resistors are connected in parallel, the resultant value is

1. $\frac{\mathrm{x}}{\mathrm{n}}$

2. $\frac{\mathrm{x}}{{\mathrm{n}}^2}$

3. ${\mathrm{n}}^2\mathrm{x}$

4. $\mathrm{nx}$

The same mass of aluminium is drawn into two wires; 1mm and 2mm thick. Two wires are connected in series and current is passed through them. The heat produced in the wires is in the ratio of

1. 16 : 1

2. 8 : 32

3. 8 : 2

4. 4 : 2

In a circuit shown in the figure, the heat produced in 3 ohm resistance due to a current flowing in it is 12 J. The heat produced in 4 ohm resistor is:

1. 2 J

2. 4 J

3. 64 J

4. 32 J

Refer to the circuit shown. What will be the total power dissipation in the circuit if P is the power dissipated in R₁? It is given that ${\mathrm{R}}_2=4 {\mathrm{R}}_1$ and ${\mathrm{R}}_3=12 {\mathrm{R}}_1$.

1. 4P

2. 7P

3. 13P

4. 17P

Three identical resistors ${\mathrm{R}}_1={\mathrm{R}}_2={\mathrm{R}}_3$ are connected as shown to a battery of constant e.m.f. The power dissipated is:

1. The least in R₁

2. Greatest in R₁

3. In the ratio of 1 : 2 in resistance R₁ and R₂ respectively

4. The same in R₁ and in the parallel combination of R₂ and R₃

Four equal resistances dissipated 5 W of power together when connected in series to a battery of negligible internal resistance. The total power dissipated in these resistances when connected in parallel across the same battery would be:

1. 125 W

2. 80 W

3. 20 W

4. 5 W

A cell sends a current through a resistance R for time t. Now the same cell sends current through another resistance r for the same time. If the same amount of heat is developed in both the resistances, then the internal resistance of the cell is:

1. $\frac{(\mathrm{R}+\mathrm{r})}{2}$

2. $\frac{(\mathrm{R}-\mathrm{r})}{2}$

3. $\frac{\left(\mathrm{Rr}\right)}{2}$

4. $\sqrt{\left(\mathrm{Rr}\right)}$

According to this diagram, the potential difference across the terminals is:

(internal resistance of cell=r)

1. $\mathrm{V}=\mathrm{E}-\mathrm{ir}$

2. $\mathrm{V}=\mathrm{E}+\mathrm{ir}$

3. $\mathrm{V}=\mathrm{E}$

4. Zero

The value of current through 2$\mathrm{\Omega }$ is:

1. 1.0 A

2. 1.5 A

3. 5.0 A

4. 2.1 A

The reading of the ammeter in the circuit below is:

1. 5 A

2. 15 A

3. 20 A

4. 25 A