# Network Theory Questions and Answers – Ohm’s Law

This set of Network Theory Multiple Choice Questions & Answers (MCQs) focuses on “Ohm’s Law”.

**1. Which of the following bulbs will have high resistance?**

**a) 220V, 60W**

b) 220V,100W

c) 115V,60W

d) 115V,100 W

**Explanation:** Resistance is inversely proportional to power and directly proportional to square of voltage.

**2. Ohm’s law is not applicable to ___________**

a) dc circuits

b) high currents

c) small resistors

**d) semi-conductors**

**Explanation:** Semiconductors and insulators are exempt from Ohm’s law.

**3. Conductance is expressed in terms of ___________**

**a) mho**

b) mho/m

c) ohm/m

d) m/ohm

**Explanation**: The reciprocal of resistance is conductance, which is measured in mho.

**4. Resistivity of a wire depends on ___________**

a) length of wire

b) cross section area

**c) material**

d) all of the mentioned

**Explanation:** A wire’s resistivity is a constant that is determined by the type of material used.

**5. In a current-voltage relationship graph of a linear resistor, the slope of the graph will indicate ___________**

**a) conductance**

b) resistance

c) resistivity

d) a constant

**Explanation:** The slope of the graph represents the current-to-voltage ratio, which represents conductance.

**6. Resistance of a wire is yΩ. The wire is stretched to triple its length, then the resistance becomes ___________**

a) y/3

**b) 3y**

c) 6y

d) y/6

**Explanation**: A conductor’s resistance is directly proportionate to its length. That is, if the length of a conductor is tripled, the resistance of the conductor is also tripled.

**7. An electric current of 10 A is the same as ___________**

a) 10 J/C

b) 10 V/C

**c) 10C/sec**

d) 10 W/sec

**Explanation:** Electric current can be defined mathematically as the ratio of the charge to the time it takes for the charge to flow.

**8. Consider a circuit with two unequal resistances in parallel, then ___________**

a) large current flows in large resistor

b) current is same in both

**c) potential difference across each is same**

d) smaller resistance has smaller conductance

**Explanation:** The potential difference between each resistor in a parallel set of resistors is the same.

**9. In which of the following cases is Ohm’s law not applicable?**

a) Electrolytes

b) Arc lamps

**c) Insulators**

d) Vacuum ratio values

**Explanation:** It only applies to conductors, according to Ohm’s law. As a result, Ohm’s law does not apply to insulators.

**10. A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is V. If the diameter of wire is made d/4, then drift velocity becomes ___________**

a) V/16

**b) 16V**

c) V

d) V/4

**Explanation:** Drift velocity is proportional to material area, i.e., V=I/nAq.

According to Ohm’s law, the current flowing through a conductor between two places is proportional to the voltage across the conductor. When the proportionality constant, resistance, is added, the conventional mathematical equation that expresses this relationship emerges: The law was named after German physicist Georg Ohm, who detailed measurements of applied voltage and current across basic electrical circuits incorporating varying lengths of wire in a paper published in 1827. Ohm’s experimental results were explained by a slightly more complicated equation than the present one (see History below).