Ohm's Law in Scalar Form

Q. The V-i graph for a conductor at temperature $T_1$ and $T_2$ are as shown in the figure. $(T_2-T_1)$ is proportional to

1. $cos2\theta$
2. $sin\theta$
3. $cot2\theta$
4. $tan\theta$

Q. Two wires of the same material having lengths in the ratio 2:3, are connected in series. The potential differences across the wires are 4.2V and 3.6V respectively. The ratio of their radii would be:

1. $2:\sqrt{7}$
2. $\sqrt{7}:2$
3. $2:7$
4. $7:2$

Q. From the graph between current I and voltage V shown in figure, identify the portion corresponding to negative resistance.

1. $DE$
2. $CD$
3. $BC$
4. $AB$

Q. Figure represents a part of the closed circuit. If a current of 2A flows in from A, the potential difference between points A and B $(V_A-V_B)$ is

1. + 9 V
2. – 9 V
3. + 3 V
4. + 6 V

Q. Calculate the emf and internal resistance of the equivalent cell to replace the below combination of cells

1. $\frac{4}{7}\text{V},\frac{1}{7}\Omega$
2. $4\text{V},2\Omega$
3. $\frac{4}{7}\text{V},\frac{2}{7}\Omega$
4. $\frac{2}{7}\text{V},\frac{1}{7}\Omega$

Q. The current through a resistor of $2\Omega$ is 1 A. What is the potential difference across it?

1. 2V
2. 4V
3. $\frac{1}{2V}$
4. 1V

Q. Equal potentials are applied on an iron and copper wire of same length. In order to have same current flow in the wire, the ratio $\left(\frac{r_{iron}}{r_{copper}}\right)$ of their radii must be [ Given that specific resistance of iron $=1.0\times {10}^{-7}\Omega m$ and that of copper $=1.7\times {10}^{-8}\Omega m$ ]

1. About 1.2
2. About 2.4
3. About 3.6
4. About 4.8

Q. Figure represents a part of the closed circuit. If a current of 2A flows in from A, the potential difference between points A and B $(V_A-V_B)$ is

1. + 9 V
2. – 9 V
3. + 3 V
4. + 6 V

Q.

When a potential difference of 2V is applied across a resistor, you observed a current I. When the length of the resistor is doubled without changing the thickness, what is the current observed when 2V is applied across it.

1. I

2. I/2

3. 2I

4. 4I