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
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
Explanation: Semiconductors and insulators are exempt from Ohm’s law.
3. Conductance is expressed in terms of ___________
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
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 ___________
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 ___________
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
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?
b) Arc lamps
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 ___________
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).