Physics

Electrical Machines and Circuits

754 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

In an electrical circuit, ammeter and voltmeter are connected in ___________ and _____________ to measure the current and voltage, respectively across the resistance.

  1. parallel, parallel

  2. parallel, series

  3. series, parallel

  4. series, series

  5. -
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer.  In an electrical circuit, ammeter is connected in series because of same current is passed through in circuit when connected in series  and voltmeter is connected in parallel.

Multiple choice

What is open circuit?

  1. A complete electrical circuit in which current can flow.

  2. An incomplete electrical circuit through which current cannot flow.

  3. The circuit in which equal amount of current passes through all the components.

  4. The circuit in which different amounts of current flows through the different appliances of a circuit.

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is an open circuit.

Multiple choice

An electric bulb lights up only when _______.

  1. circuit is open

  2. circuit is closed

  3. when connected to proper terminal

  4. when we switch on the plug

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When circuit is closed, then current easily passes through it and bulb will blink.

Multiple choice

For which of the following purposes is a transformer used?

  1. Conversion of DC into AC

  2. Regulation of fluctuation of voltage

  3. Measurement of flow of electricity

  4. Conversion of low voltage into high voltage and vice versa
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Correct Answer: Conversion of low voltage into high voltage and vice versa

Multiple choice

During which test of the induction motor, the reduced voltage is applied?

  1. No lead test

  2. Blocked rotor test

  3. Insulation test

  4. Resistance test
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The blocked rotor test applies reduced voltage to the motor while keeping the rotor stationary, measuring current and power to determine equivalent circuit parameters. This test is also called the locked-rotor test and helps determine starting torque characteristics.

Multiple choice

Which of the following statements is/are true?

  1. Half wave rectifier allows AC to flow continuously in one direction.

  2. Full wave rectifier allows AC to flow continuously in one direction.

  3. Rectification is done by a device known as amplifier.

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

Full wave rectifier allows AC to flow continuously in one direction.

Multiple choice

Why is the parallel electric circuit better for connecting bulbs in a house?

  1. The overall resistance of the circuit increases too much.

  2. Electrical appliance gets the same voltage.

  3. Electrical appliances have only one switch.

  4. If one electrical appliance stops working, then the others also stop working.

  5. They have a single operation.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In parallel circuits, each electrical appliance gets the same voltage as that of the power supply line.

Multiple choice

In case of the failure of static source, what is recommended action to be taken?

  1. Turn the battery off.

  2. Break the glass of VSI.

  3. Restart the magnetos.

  4. Squawk 7600 on Mode C.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the static source fails, breaking the glass of the VSI (Vertical Speed Indicator) provides an alternate static source because the VSI case is connected to the static system. This is a standard emergency procedure in many aircraft. The other options are irrelevant - turning off the battery, restarting magnetos, or squawking 7600 (radio failure code) do not address static system failure.