Skip to main content

Class 7 Science NCERT Chap 14 Solution

 Chapter 14

ELECTRIC CURRENT AND ITS EFFECTS

Here is answer of chapter 14 ELECTRIC CURRENT AND ITS EFFECTS NCERT science of class 7 which helps students to better understand topics of chapter 14 ELECTRIC CURRENT AND ITS EFFECTS.

Exercise Questions-

Ques 1.Draw in your notebook the symbols to represent the following components of electrical  circuits: connecting wires switch wires, switch in the OFF position, bulb, cell, switch in the ON position and battery.
Ans.
class-7-chap-14-science


Ques 2. Draw the circuit diagram to represent the circuit shown in figure.
class-7-chap-14-science

Ans.
class-7-chap-14-science




Ques 3. Figure 14.22 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.
class-7-chap-14-science


Ans. To construct a battery, the negative terminal of one cell should be connected to the positive terminal of the other cell. Therefore the cells should be connected as shown in figure.
class-7-chap-14-science




Ques 4. The bulb in the circuit shown in Fig 14.23 does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulb glow.
class-7-chap-14-science


Ans. Terminals of the battery should be connected properly. Positive terminal of one battery should be connected to the negative terminal of another battery.


Ques 5. Name any two effect of electric current.
Ans. A current carrying conductor can show a heat effect and a electron magnetic effect  which can be considered as the two effects of electric current.

Ques 6. When the current is switched on through a wire, a compass needle kept nearby gets deflected from the north south position. Explain.
Ans.  A current carrying wire creates a magnetic field around it. The needle of  a compass is a tiny  magnet which points in a north south direction with a compass  needle nearby and current is allowed to pass through it, the magnetic  field of the compass  needle, hence it shows a deflection.

Ques 7. Will the compass needle show deflection   when the switch in the circuit shown by Fig 14.24 is closed?
class-7-chap-14-science


Ans. From the given circuit we observe that there is neither a cell nor a battery. Hence, there  is no source of electricity. Through the switch in the circuit is closed,there is no passage of current. Hence, it does not show any effect on the magnetic needle kept close by the circuit. 

Ques 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)produces heat
d) fuse 

Ques 9. Mark 'T' if the statement is True and 'F' if is False:-
a)To make a bsttery 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 break.
c)An electromagnet does not attract a piece of iron(T/F)
d)An electric bell has an electromagnet.(T/F)
Ans. a)false
b)True
c)false
d)True

Ques 10. Do you think an electro magnet can be 
used for seperating plastic bags from a garbage heap? Explain.
Ans. No, an electro magnet cannot be used for seperating plastic bags from garbage heap. Electromagnets are used to seperate magnetic materials from the junk. As, plastic is a non magnetic  materials it cannot be seperated  from the junk using electromagnets.

Ques 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. Wires made from some special materials melt quickly and break when large electric currents are passed through them. These materials  are used in electric fuses which prevent fires and damage to electric   fuses which  prevent fires and damage  to electric appliances.
Therefore, I would not agree to replace a fuse by  a piece of wire has particular properties. Any wire has particular properties. Any wire cannot  act as fuse wire. We should always use proper uses which have been specified for particular applications, carrying the ISI mark which indicates that the advice is manufactured according  to standard.

Ques 12.Zubeda made an electric circuit using a cell  holder shown in Fig.14.4 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.
CLASS-7-SCIENCE-CHAP-14


Ans. Possible defects can be as follows:-
a)The two cells may not be connected properly.
b)The rubber band used in the cell holder is unable to hold the cells in contacts with each other and the circuit is incomplete  and current is not following in the circuit.
The following conditions are to be satisfied for the  bulb to glow:-
a)The positive terminal  of the cell should be connected to the negative terminal of another cells.
b) Check the wire connections properly.
c) Check the condition of the bulb whether it is working or fused.

Ques 13. In the circuit shown in Fig.14.25.
CLASS-7-SCIENCE-CHAP-14


I)Would any of the bulb glow  when the switch is in the Off  position?
Ans. No bulb will glow when the switch is in the Off position are there is no current in the circuit 
Unless and untill the switch is in the ON position  no bulb will glow.

ii) 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. When the switch is in the ON all the bulbs will glow at the same time as they are connected to the same battery and switch.


This is the complete solution and explaination of Chapter 14 ELECTRIC CURRENT AND ITS EFFECT of Class 7 Science NCERT.

We are here to solve your queries.
Contact us if you have any doubt.

You can also Access-

Comments

Popular posts from this blog

CLASS 8 SCIENCE CHAPTER 7 Conservation of Plants And Animals SOLUTION for 2020-21

CHAPTER 7 \ CONSERVATION OF PLANTS AND ANIMALS Here is some important points and answer  of chapter 7 CONSERVATION OF PLANTS AND ANIMALS  NCERT science of class 8 which helps students to  better understand topics of chapter 7 CONSERVATION OF PLANTS AND ANIMALS. KEYNOTES OF CHAPTER 7: 1.BIODIVERSITY : BIODIVERSITY refers to the variety of living organisms in a specific area. 2. BIOSPHERE RESERVE :- BIOSPHERE RESERVE are the area meant for conservation of biodiversity. 3 .DEFORESTATION :- Cutting down of trees is called deforestation. 4. DESERTIFICATION:- The fertile land gets converted into deserts.It is called desertification. 5.ECOSYSTEM:- An ecosystem is  made of all the plants,animals and microorganisms  in an area along with non living components such as climate,soil,river deltas etc. 6 .Endangered species:- Endangered species   are those which are facing the danger of extinction. 7.Endemic species:-    Endemic species  are found only in a particular area. 8.Fauna:- The animals of

Class 8 science CHAPTER 3 SOLUTION

 CHAPTER 3  SYNTHETIC FIBRES AND PLASTICS CHAPTER 3 SYNTHETIC FIBRES AND PLASTICS of CLASS 8 SCIENCE NCERT is here with complete solution of all the textbook questions of CHAPTER 3. All the NCERT solutions are framed in a systematic manner, according to the latest CBSE Class 8 science syllabus (2020-21). After studying this   you will be able to understand the topics covered in the chapter thoroughly. It is noticed that many questions are directly asked in previous year class 8 examinations. In order to score good marks in the examination, students should study this material in-depth. Here's the answer of textbook questions of CHAPTER 3 SYNTHETIC FIBRES AND PLASTICS. Exercise Questions. Q1. Explain why some fibres are called synthetic. Ans. There are some fibres that are made by man using chemicals.These are called synthetic fibres. These are made up of small units that are joined together to form a long chains called POLYMER. For example: Rayon,Nylon,etc Q2. Mark (✓) the correct a

Class 7 Science NCERT Chap 2

CHAPTER 2  NUTRITION IN ANIMALS Here is some important points and answer of chapter 2 NUTRITION IN ANIMALS NCERT science of class 7 which helps students to better understand topics of chapter 2 NUTRITION IN ANIMALS. Keywords :- a) Absorption:- Absorbing of digested food by the small intestine is known as Absorption. b)Amoeba:- It is unicellular organism which can change its shape. c) Assimilation:- Transfer of digestion food  and its utilisation is known as assimilation. d)Egestion:- Removing out waste from body is known Egestion. e)Bile:- A yellowish liquid release from liver. f)Villi:- Finger like projection present in small intestine help in absorb digested food. g)Digestion:- The break down of complex form of food into simple form is known as Digestion. h) Ruminant:- The animals which chew cud are called Ruminants. These are the important keynotes of Chapter 2 Nutrition in Animals. Here is the Solution Of textbook CHAPTER 2 Nutrition In Animals. Exercise Questions- Ques 1. Fill in