State Whether the Following Statements Are True Or False. an Electric Motor Converts Mechanical Energy into Electrical Energy. - Science

True or False

State whether the following statement is true or false.

An electric motor converts mechanical energy into electrical energy.


  • True

  • False




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Chapter 13: Magnetic Effects of Electric Current - Exercises [Page 240]


NCERT Science Class 10
Chapter 13 Magnetic Effects of Electric Current
Exercises | Q 6.2 | Page 240

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 State the principle of an electric generator.

The device used for producing electric current is called a ______.

What is the function of brushes in an electric generator?

What is the major difference between the simple alternator and most practical alternators? 

Complete the following sentence: 

A generator with commutator produces ............... current. 

 Explain the principle of an electric generator. 

Each one of the following changes will increase emf (or voltage) in a simple generator except: 

(a) increasing the number of turns in the armature coil
(b) winding the coil on a soft iron armature
(c) increasing the size of the gap in which the armature turns
(d) increasing the speed of rotation

An electric generator converts:

(a) electrical energy into mechanical energy.
(b) mechanical energy into heat energy.
(c) electrical energy into chemical energy.
(d) mechanical energy into electrical energy. 

State whether the following statement are true of false: 

A miniature circuit breaker (MCB) works on the heating effect of current.

Name and state the principle of a simple a.c. generator what is its use?

Draw a labelled diagram of a simple a.c. generator.

In an a.c. generator the speed at which the coil rotates is doubled. How would this affect (a) the frequency of output voltage, (b) the maximum output voltage is doubled.

Suggest two ways in an a.c. generator to produce a higher e.m.f.

State two dis-similarities and one similarity between a d.c. motor and an a.c. generator.

Explain the construction and working of the following. Draw a neat diagram and label it.

Electric Generator (AC)

Explain the difference:
AC generator and DC generator.

Observe the figure and answer the following questions.
a) Identify the machine shown in figure.
b) Write a use of this machine.
c) How transformation of energy takes place in this machine.

Draw a neat labeled diagram of an A.C. generator 

Complete the sentence:

An a.c. generator changes the ___________ energy to ___________ energy. 

Explain the construction and working of an electric generator (AC) with the help of a neat diagram.

A flat coil of wire rotates at a constant speed about an axis perpendicular to a uniform magnetic field. Draw a graph to show how the induced e.m.f. varies relative to the positions of the coil during its one complete rotation. At what position of the coil, the e.m.f. has the maximum value?

State change that you would make to convert an A.C. generator into a D.C. generator. Illustrate the change by a diagram.

The given figures 1 to 3 show the working of a simple A.C. generator. Study the diagrams and answers of the following questions.

(i) State and explain the principle underlying the working of a simple generator.
(ii) Where is the loop of wire placed?
(iii) What happens when the loop is rotated?
(iv) Indicate the direction of the current flow through the wire for the first half of the turn (in first figure). Name and state the rule used in finding the direction of the current.
(v) Indicate the direction of the current for the case shown in second figure. 
(vi) Indicate the direction of current in the outer circuit (i.e., electric bulb) in first and third figure.
(vii) What type of current is shown in the above diagrams? Explain.

State true or false:

The frequency of AC is 50 Hz.

Observe the figure and write the answers to the questions asked.

  1. The construction shown in the figure is of which device?
  2. Explain the principle on which this device works.
  3. Write any three uses of this device.

The part of the AC generator that passes the current from the armature coil to the external circuit is ______.

A device for producing electric current is ______.

Draw and label the diagram of an AC generator.

Draw a neat diagram of an AC generator and explain its working.

A coil of insulated copper wire is connected to a galvanometer forming a loop and a magnet is:

A: Held stationary

B: Moved away along its axis

C: Moved towards along its axis

D: There will be an induced current in

A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is held stationary inside the coil?

An AC generator is provided with ______ slip rings that rotate with the coil.

Observe the following diagram and answer the questions.

  1. Explain the construction of the equipment shown in the figure.
  2. How is AC generated?


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