Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 13: Problem 6

State whether the following statements are true or false. (a) An electric motor converts mechanical energy into electrical energy. (b) An electric generator works on the principle of electromagnetic induction. (c) The field at the centre of a long circular coil carrying current will be parallel straight lines. (d) A wire with a green insulation is usually the live wire of an electric supply.

Short Answer

Expert verified
(a) False, (b) True, (c) True, (d) False

Step by step solution

01

Analyze Statement (a)

An electric motor converts electrical energy into mechanical energy, not the other way around. Therefore, statement (a) is false.
02

Analyze Statement (b)

An electric generator indeed works on the principle of electromagnetic induction, where a changing magnetic field induces an electromotive force (EMF). Therefore, statement (b) is true.
03

Analyze Statement (c)

The magnetic field at the center of a long circular coil carrying current is uniform and straight, resembling parallel lines. Therefore, statement (c) is true.
04

Analyze Statement (d)

A wire with green insulation is typically used as the earth (or ground) wire in an electrical system, not the live wire. Therefore, statement (d) is false.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Electric Motor
An electric motor is a device that converts electrical energy into mechanical energy. The core principle behind this is the interaction between the magnetic field and the electric current.

When a current flows through a coil of wire in a magnetic field, it experiences a force which causes it to move. This movement is harnessed to perform mechanical work.

Key points to remember about electric motors:
  • They operate on direct current (DC) or alternating current (AC).
  • They use the principles of electromagnetism to generate motion.
  • Common applications include fans, pumps, and mixers.

    To summarize, an electric motor does not convert mechanical energy to electrical energy. Hence, the statement (a) in the exercise is false.
Electromagnetic Induction
Electromagnetic induction is the process by which a change in magnetic field creates an electromotive force (EMF) or voltage in a conductor. This is the fundamental principle behind electric generators.

Here are some important aspects of electromagnetic induction:
  • Faraday's Law describes how a current is induced via a changing magnetic field.
  • This principle is utilized in various applications, including transformers and induction cooktops.
  • It is crucial for the functioning of devices that convert mechanical energy to electrical energy, like generators.

Thus, electromagnetic induction underlies the working of an electric generator, making statement (b) in the exercise true.
Current-Carrying Coil
A current-carrying coil, often termed as a solenoid when long and cylindrical, generates a magnetic field when an electric current passes through it. The configuration of the coil affects the shape and nature of the magnetic field it produces.

In the center of a long solenoid, the magnetic field lines are parallel and uniform, resembling straight lines. Important points include:
  • The strength of the magnetic field is proportional to the number of turns in the coil and the current flowing through it.
  • The direction of the magnetic field follows the right-hand rule.
  • Applications range from electromagnets to inductors and various types of sensors.

Based on this understanding, the magnetic field at the center of a current-carrying coil appears as parallel straight lines, verifying that statement (c) in the exercise is true.
Electrical Wiring
Identifying electrical wiring correctly is crucial for ensuring safety and proper functioning of electrical systems. Wires are color-coded for easy identification.

One of the standard color codes includes:
  • Green or green-yellow striped wires are usually used as earth (or ground) wires.
  • Black or red wires are commonly used as live wires (those that carry current).
  • White or grey wires are typically neutral wires.

Therefore, understanding that a wire with green insulation is the earth wire and not the live wire helps ensure accuracy and safety. Thus, statement (d) in the exercise is false.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The essential difference between an AC generator and a DC generator is that (a) AC generator has an electromagnet while a DC generator has permanent magnet. (b) DC generator will generate a higher voltage. (c) AC generator will generate a higher voltage. (d) AC generator has slip rings while the DC generator has a commutator.

Which of the following correctly describes the magnetic field near a long straight wire? (a) The field consists of straight lines perpendicular to the wire. (b) The field consists of straight lines parallel to the wire. (c) The field consists of radial lines originating from the wire. (d) The field consists of concentric circles centred on the wire.

Name some devices in which electric motors are used.

When is the force experienced by a current-carrying conductor placed in a magnetic field largest?

The phenomenon of electromagnetic induction is (a) the process of charging a body. (b) the process of generating magnetic field due to a current passing through a coil. (c) producing induced current in a coil due to relative motion between a magnet and the coil. (d) the process of rotating a coil of an electric motor.
See all solutions

Recommended explanations on Physics Textbooks

Kinematics Physics

Read Explanation

Measurements

Read Explanation

Further Mechanics and Thermal Physics

Read Explanation

Electric Charge Field and Potential

Read Explanation

Circular Motion and Gravitation

Read Explanation

Translational Dynamics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free