A carbon resistor has coloured strips as shown in the figure. What is its resistance?

1. $410 \mathrm{\Omega }\pm 2\%$

2. $470 \mathrm{\Omega }\pm 5\%$

3. $420 \mathrm{\Omega }\pm 3\%$

4. $405 \mathrm{\Omega }\pm 2\%$

A wire has a resistance of 12 ohms. It is bent in the form of a circle. The effective resistance between the two points on any diameter of the circle is:

1. $12 \mathrm{\Omega }$

2. $24 \mathrm{\Omega }$

3. $3 \mathrm{\Omega }$

4. $6 \mathrm{\Omega }$

A technician has only two resistance coils. By using them singly, in series or in parallel, he is able to obtain the resistance 3, 4, 12 and 16 ohms. The resistance of the two coils are:

1. 6 and 10 ohms

2. 4 and 12 ohms

3. 7 and 9 ohms

4. 4 and 16 ohms

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. $\sqrt{\left(\mathrm{Rr}\right)}$