Ohm's Law and Resistance

Q. An unknown circuit draws a current of 2 A from a 12 V battery its equivalent resistance is ________________.

1. 24 Ω
2. 6 Ω
3. 0.167 Ω
4. 10 Ω

Q. A 6 V battery is connected across a lamp whose resistance is 20 $\Omega$. Calculate the value of the extra resistance in $\Omega$ which must be used in the circuit to get 0.25 A current in the circuit.

1. 4 $\Omega$

2. 6 $\Omega$

3. 2 $\Omega$

4. 8 $\Omega$

Q. According to ohm's law, the plot of the electric current vs the potential difference in a circuit gives a straight line .

1. with constant slope
2. parallel to current axis
3. parallel to voltage axis

Q. Considering the relation between current $I$, voltage $V$ and resistance $R$, which of the following equations is/are TRUE?

1. $V^2=I^2{R}^2$
2. $R^{-2}=V^{-2}{I}^2$
3. $V^2=R{I}^{-2}$
4. $V^{-2}=R^2{I}^{-2}$

Q. Calculate the resistance of a wire, if the voltage is $48\text{V}$ and the current flowing is equal to $4\text{A}$.

1. 12

Q. LED is an example of a non-ohmic conductor.

1. True
2. False

Q. Ohm's law is applicable irrespective of the temperature.

1. True
2. False

Q. An electric bell has a rating of 500 W and 100 V. It is used in a circuit having a 200 V supply. What resistance must be connected in series with the bulb so that it delivers 500 W?

1. 10 $\Omega$
2. 20 $\Omega$
3. 30 $\Omega$
4. 40 $\Omega$

Q. Ohm's law cannot be applied to:

1. Germanium
2. Metals
3. Silicon
4. Gases

Q. The conductance of a 4.5 kilo ohm resistor is .

1. $0.458m{\Omega }^{-1}$
2. $1.386m{\Omega }^{-1}$
3. $0.222m{\Omega }^{-1}$