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Watt’s Law Question & Answers

May 30, 2023 By Wat Electrical

This article lists 50 Watt's Law MCQs for engineering students. All the Watt's Law  Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of Watt's Law.

Watt's Law (unofficial term) states that the power (P) in an electrical circuit is equal to the product of the voltage (V) across a device and the current (I) flowing through it. Mathematically, it can be expressed as P = V * I.

This formula indicates that power is directly proportional to both voltage and current. It implies that increasing either the voltage or the current will result in a corresponding increase in power, given that the other value remains constant. Power is the rate at which electrical energy is transferred or consumed in a circuit.

It's important to note that this formula holds true for resistive circuits, where the voltage and current are in phase. Additional considerations such as power factor come into play in more complex circuits involving reactive components like capacitors and inductors.

This law is mainly used for discovering or analyzing the voltage, ampere, resistance, & power. Watts can be utilized to decide the performance of the battery.

1). What is the formula for calculating power in an electrical circuit?

Hint
2). A circuit has a voltage of 12 volts and a current of 2 amperes. What is the power consumed by the circuit?

Hint
3). In an electrical circuit, the power dissipated is 60 watts, and the current flowing through it is 3 amperes. What is the voltage across the circuit?

Hint
4). If the power consumed by a device is 500 W and the voltage across it is 100 V, what is the current flowing through the device?

Hint
5). Who formulated Watts' Law?

Hint
6). When was Watts' Law formulated?

Hint
7). What is the mathematical equation representing Watts' Law?


Hint
8). Which of the following is not one of the variables in Watts' Law?

Hint
9). What does Watts' Law describe?

Hint
10). A circuit has a power of 200 watts and a voltage of 20 volts. What is the current flowing through the circuit?

Hint

Watt's Law  MCQ for Exams

11). In a circuit, the current is 5 amperes, and the power dissipated is 1000 watts. What is the voltage across the circuit?

Hint
12). A resistor has a power rating of 5 watts and a voltage across it of 10 volts. What is the maximum current that can flow through the resistor?

Hint
13). A circuit has a resistance of 20 ohms and a current of 2 amperes. What is the power dissipated in the circuit?

Hint
14). The power dissipated in a circuit is 500 watts, and the resistance is 50 ohms. What is the current flowing through the circuit?

Hint
15). Watt's Law relates power, voltage, and current in an electrical circuit. Which of the following is a key feature of Watt's Law?

Hint
16). Which of the following statements accurately describes the relationship between voltage and current in Watt's Law?

Hint
17). In Watt's Law, if the power remains constant, what happens to the current when the voltage is doubled?

Hint
18). Which of the following is an advantage of Watt's Law in electrical calculations?

Hint
19). Watt's Law is applicable to which type(s) of electrical circuits?

Hint
20). What advantage does Watt's Law offer in terms of circuit analysis?

Hint
21). Which of the following principles is encompassed by Watt's Law?

Hint
22). Watt's Law is an application of which fundamental electrical principle?

Hint
23). What is the underlying principle behind Watt's Law?

Hint
24). Watt's Law is commonly used in which of the following applications?

Hint
25). Which of the following is an example of an application of Watt's Law?

Hint
26). Watt's Law is utilized in which of the following electrical devices?

Hint
27). Watt's Law is based on the principle of conservation of ________________?

Hint
28). In a circuit, the voltage is 10 volts, and the current is 2 amperes. What is the power consumed by the circuit?

Hint
29). If a circuit has a resistance of 5 ohms and a current of 2 amperes, what is the voltage across the circuit?

Hint
30). A device operates at a power of 60 W and is connected to a 120 V power source. What is the current flowing through the device?

Hint
31). What happens to the power in an electrical circuit if both the voltage and current are doubled?

Hint
32). In terms of electrical quantities, Watt's Law is classified as a relationship between:

Hint
33). Watt's Law falls under the category of which fundamental laws of physics?

Hint
34). Which of the following scientists provided the theoretical foundation for Watt's Law?

Hint

Watt's Law MCQ for Interviews

35). Which formula is used to calculate current using Watt's Law?

Hint
36). Which formula is used to calculate voltage using Watt's Law?

Hint
37). Which law relates current, voltage, and resistance in an electrical circuit?

Hint
38). Which law states that the power in a circuit is equal to the product of voltage and current?

Hint
39). What is the mathematical formula for Ohm's Law?

Hint
40). Which law is used to calculate the power dissipated in a circuit?

Hint
41).Which function or setting on a DMM should be selected to measure DC voltage?

Hint
42). What is the typical range for measuring DC voltage on a DMM?

Hint
43). When connecting a DMM to measure voltage, which terminals of the DMM should be used?

Hint
44). If the DMM reads "OL" when measuring voltage, what does it indicate?

Hint
45). What is the proper technique for measuring voltage with a DMM?

Hint
46). Which mode should you select on a DMM to measure current in a circuit?

Hint
47). If the current being measured exceeds the range selected on the DMM, what is likely to happen?

Hint
48). When connecting a DMM in series to measure current, how should the DMM be connected in the circuit?

Hint
49). If a DMM has multiple current ranges (e.g., 200mA, 2A, 10A), which range should you initially select to measure a current of 400mA?

Hint
50). What is the typical input impedance of a DMM when measuring current?

Hint

For More MCQs

  • Kirchhoff’s Law Question & Answers.
  • Ohms Law Question & Answers.

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