eVidyarthi

Main Menu
  • eVidyarthi
  • School
    • Class 6th
      • Maths Class 6
      • Science Class 6
      • Hindi Class 6
      • व्याकरण
      • English Class 6
      • English Grammar
      • Sanskrit Class 6
      • Geography
      • Civics
      • History
    • Class 7th
      • Maths Class 7
      • Science Class 7
      • Hindi Class 7
      • व्याकरण
      • English Class 7
      • English Grammar
      • Sanskrit Class 7
      • Geography
      • Civics
      • History
    • Class 8th
      • Maths Class 8
      • Science Class 8
      • Hindi Class 8
      • व्याकरण
      • English Class 8
      • English Grammar
      • Sanskrit Class 8
      • Geography
      • Civics
      • History
    • Class 9th
      • Maths Class 9
      • Science Class 9
      • Hindi Class 9
      • व्याकरण
      • English Class 9
      • English Grammar
      • Economics Class 9
      • Geography Class 9
      • Civics Class 9
      • History Class 9
      • Sanskrit Class 9
    • Class 10th
      • Maths Class 10
      • Science Class 10
      • Hindi Class 10
      • व्याकरण
      • English Class 10
      • English Grammar
      • Economics Class 10
      • Geography Class 10
      • Civics Class 10
      • History Class 10
      • Sanskrit Class 10
    • Class 11th
      • Maths Class 11
      • Accounts Class 11
      • Chemistry Class 11
      • व्याकरण
      • Physics Class 11
      • English Grammar
      • English Class 11
      • Biology Class 11
    • Class 12th
      • Maths Class 12
      • Accounts Class 12
      • Chemistry Class 12
      • व्याकरण
      • Physics Class 12
      • English Grammar
      • English Class 12
      • Biology Class 12
    • Close
  • School (हिन्दी Medium)
    • Class 6
      • हिन्दी Class 6
      • English Grammar
      • व्याकरण
      • गणित Class 6
      • विज्ञान Class 6
      • सामाजिक विज्ञान Class 6
      • English Class 6
      • संस्कृत Class 6
    • Class 7
      • हिन्दी Class 7
      • English Grammar
      • व्याकरण
      • गणित Class 7
      • विज्ञान Class 7
      • सामाजिक विज्ञान Class 7
      • English Class 7
      • Sanskrit Class 7
    • Class 8
      • Hindi Class 8
      • English Grammar
      • व्याकरण
      • गणित Class 8
      • विज्ञान Class 8
      • सामाजिक विज्ञान Class 8
      • English Class 8
      • Sanskrit Class 8
    • Class 9
      • Hindi Class 9
      • English Grammar
      • व्याकरण
      • गणित Class 9
      • विज्ञान Class 9
      • सामाजिक विज्ञान Class 9
      • English Class 9
      • Sanskrit Class 9
    • Class 10
      • Hindi Class 10
      • English Grammar
      • व्याकरण
      • गणित Class 10
      • विज्ञान Class 10
      • सामाजिक विज्ञान Class 10
      • English Class 10
      • Sanskrit Class 10
    • Class 11
      • गणित Class 11
      • जीव विज्ञान Class 11
      • रसायन विज्ञान Class 11
      • भौतिक विज्ञान Class 11
      • भूगोल Class 11
      • इतिहास Class 11
      • राजनितिक विज्ञान
      • अर्थशास्त्र Class 11
      • समाजशास्त्र Class 11
    • Class 12
      • गणित Class 12
      • जीव विज्ञान Class 12
      • रसायन विज्ञान Class 12
      • भौतिक-विज्ञान Class 12
      • भूगोल Class 12
      • इतिहास Class 12
      • राजनितिक विज्ञान
      • अर्थशास्त्र Class 12
      • समाजशास्त्र Class 12
    • Close
  • English
    • Basic English Grammar
    • Basic English Speaking
    • English Vocabulary
    • English Idioms & Phrases
    • Personality Enhancement
    • Interview Skills
    • Close
  • Softwares
    • Microsoft Word
    • PhotoShop
    • Excel
    • Illustrator
    • PowerPoint
    • Close
Science Class 7 || Menu
  • Important
    • Sample Paper Class 7th Science
    • NCERT Solutions
    • MCQs
    • Notes of Class 7th Science
    • Science Book Class 7
    • Close
  • Nutrition in Plants
  • Nutrition in Animals
  • Fibre to Fabric
  • Heat
  • Acids, Bases and Salts
  • Physical and Chemical Changes
  • Weather, Climate and Adaptations of Animals to Climate
  • Winds, Storms and Cyclones
  • Soil
  • Respiration in Organisms
  • Transportation in Animals and Plants
  • Reproduction in Plants
  • Motion and Time
  • Light

NCERT Solutions Class 7 Science Chapter 14 Electric Current and its Effects

Q.1.Draw in your notebook the symbols to represent the following components of electrical circuits: connecting wires, switch in the ‘OFF’ position, bulb, cell, switch in the ‘ON’ position and battery.

Ans.

Q.2.Draw the circuit diagram to represent the circuit shown in fig. 14.9.

Ans.

Q.3.Fig. 14.11 shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells.

Ans.

Q.4.The bulb in the circuit shown in fig. 14.13 does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulb glow.

Ans. Problem in this circuit is the combination of two cells. In the circuit positive terminal of one cell should be connected with negative terminal of other to make the bulb glow

Q.5. Name any two effects of electric current.

Ans. Electric current has the following effect :
(i) Electric current can give rise to heating and lighting.
(ii) Electric current can convert a straight conductor into a temporary magnet.

Q.6.When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.

Ans. When current is passed through the wire, it deflects the compass near it from its north-south position like a magnet. This is called magnetic effect of the current. As we know that needle of the compass is made up of a thin magnet. When this needle comes in contact with another magnet then the like poles of the magnet repel each other and opposite poles attract each other. So the deflection is seen in the needle. In this case the wire behaves like a magnet and causes deflection in needle of the compass.

Q.7.Will the compass needle show deflection when the switch in the circuit shown by fig. 14.15 is closed?

Ans. No, because there is no source of electric current in this circuit, i.e., there is no battery.

Q.8.Fill in the blanks:
(a) Longer line in the symbol for a cell represents its ___________terminal
(b) The combination of two or more cells is called a ____________.
(c) When current is switched ‘on’ in a room heater, it ___________.
(d) The safety device based on the heating effect of electric current is called a _____________.

Ans. (a) positive (b) battery (c) becomes red hot and emits heat (d) fuse.

Q.9.Mark ‘T’ if the statement is true and ‘F’ it is a false:
(a) To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. [T/F]
(b) When the electric current through the fuse exceeds a certain limit , the fuse wire melts and breaks. [T/F]
(c) An electromagnet does not attract a piece of iron. [T/F]
(d) An electric bell has an electromagnet. [T/F]

Ans. (a) F (b) T (c) F (d) T

Q.10. Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.

Ans. No, the plastic bags do not get attracted by the magnet, so they cannot be separated by an electromagnet. Plastic bags are not magnetic materials, only magnetic materials like iron can be attracted by the magnet.

Q.11. An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of wire. Would you agree? Give reasons for your response.

Ans. No, we would not agree to allow to replace the fuse by a wire. Wires in the fuses are of specific melting points. So wd should always use ISI marked fuses in our houses to prevent short circuits.

Q.12. Zubeda made an electric circuit using a cell holder shown in fig. 14.16, a switch and a bulb. When she put the switch in the ‘ON’ position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit

Ans. It is important to put the cells in right series. The positive terminal of the first cell should be connected with negative terminal of the second cell. The switch should be closed properly and bulb should not be fused. If Zubeda will check these then the bulb will certainly glow.

Q.13. In the circuit shown in fig. 14.17.

Would any of the bulb glow when the switch is in the ‘OFF’ position?
What will be the order in which the bulbs A, B and C will glow when the switch is moved to the ‘ON’ position?

Ans. No bulb will glow.
All bulbs will glow simultaneously.

Android App

eVidyarthi

Search On eVidyarthi

Evidyarthi on Facebook

Like us on Facebook

Follow Evidyarthi on Youtube

Learn English
Learn English Through हिन्दी
Job Interview Skills
English Grammar
हिंदी व्याकरण - Vyakaran
Mathematics Class 6th
Science Class 6th
हिन्दी Class 6th
Mathematics Class 7th
Science Class 7th
हिन्दी Class 7th
Mathematics Class 8th
Science Class 8th
हिन्दी Class 8th
Mathematics Class 9th
English Class 9th
Science Class 9th
Mathematics Class 10th
English Class 10th
Mathematics Class XI
Chemistry Class XI
Accountancy Class 11th
Accountancy Class 12th
Mathematics Class 12th
Microsoft Word
Microsoft Excel
Microsoft PowerPoint
Adobe PhotoShop
Adobe Illustrator
Learn German
Learn French
IIT JEE
Privacy Policies, Contact Us
Copyright © 2020 eVidyarthi and its licensors. All Rights Reserved.