Physics

Electrical Machines and Circuits

720 Questions

Electrical machines and circuits involve the principles of alternating and direct current, transformers, diodes, and power consumption. These concepts are essential for engineering and technical exams. Review these practice questions to test your knowledge of circuit analysis.

Transformers and impedanceAlternating and direct currentCircuit components and diodesPower consumption calculations

Electrical Machines and Circuits Questions

Multiple choice

Short circuit means

  1. direct flow of current between two points of different potential

  2. indirect flow of current between two points

  3. direct flow of current between points of the same potential

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A short circuit occurs when current flows directly between two points at different electrical potentials, bypassing the normal load or resistance in the circuit. This creates a low-resistance path that can cause excessive current flow, potentially damaging equipment or causing fires.

Multiple choice

Which of the following statements is/are false? a. The less the thickness of the connecting wire, the more is the current it can bear without getting hot. b. Filament based electric bulbs are inefficient and waste a large amount of electric energy. c. A fuse is the weakest part in an electric circuit.

  1. Only a.

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The less the thickness of the connecting wire, the more is the current it can bear without getting hot, is a false statement. Hence, it is the correct option. The more the thickness of the connecting wire, the more is the current it can bear without getting hot.  

Multiple choice

A zener diode is used as a ________.

  1. rectifier

  2. oscillator

  3. voltage regulator

  4. current limiter
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A Zener diode is specifically designed to operate in the reverse breakdown region, making it ideal for maintaining a constant voltage across a load.

Multiple choice

A thyristor is often used in

  1. wall clocks

  2. digital multimeters

  3. speed control of motors

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Thyristors, such as SCRs, are widely used in power electronics for controlling the speed of motors by regulating the power delivered to them.