Important Questions for CBSE Class 7 Science Chapter 14 – Electric Current and Its Effects

Science is not just a subject but a significant part of our lives. We cannot imagine our life without the technologies and inventions that are the precious gift from science. One such gift is electric current. Chapter 14 of Class 7 Science is about ‘Electric Current and its Effect’. Electric charges and fields give us an idea of how we made our daily life easier and more comfortable through different appliances, machines and instruments. This chapter covers the methods and ideas which led to making cells, batteries and the electric circuits used in electric iron, bulbs, remotes, motherboards etc.

To better understand the chapter, one should practice several questions to get profound knowledge and a fine grip over the concept behind each topic. Extramarks is an online learning platform and is the preferred study mate for lakhs of students across the country. We provide a variety of chapter-wise topic-related questions as part of our question bank class 7 science chapter 14 important questions. These questions are from the NCERT textbook, NCERT exemplar, other reference books, and CBSE past years’ question papers, etc. Our experienced Science subject experts have created step-by-step solutions to support the students in learning the chapter logically so that students’ interests will develop in this subject.

 Extramarks believes in incorporating joyful learning experiences through its own repository. Besides  Important Questions Class 7 Science Chapter 14, there are other study materials including NCERT Solutions, CBSE revision notes, past year question papers, NCERT books, and more.

Electric Current and Its Effects Class 7 Important Questions with solutions

Our expert Science teaching faculty members have created Class 7 Science Chapter 14 Extra Questions and answer series using references from various other sources. The questions are exam-oriented and include a variety of formats such as MCQs, fill-in-the-blanks, true or false, short answers, and long answers questions. The questions are designed and arranged so that students can revise quickly. These questions and answers help students better understand each topic covered in the chapter Electric Current and its Effects.

 At Extramarks, we understand the importance of revision notes and we take our role seriously to provide the best resource to the students and help them excel in academics. The syllabus is vast and students often get stressed about whether they will be able to complete the entire syllabus. Therefore, the subject experts have curated Important Questions to help the students with the syllabus. Following are some of the questions and their answers from our Chapter 14 Class 7 Science important questions:

Question 1. Define MCB  and write the functions of an MCB.

Answer 1. The full form of MCB is Miniature Circuit Breaker. It is a tool that works as a fuse. We can use an MCB in place of a fuse. It automatically breaks the circuit if it crosses the safe limit of electricity and prevents short circuits and other damage. An MCB can be handled manually.

Question 2. Describe Electromagnet. Also, write its properties.

Answer 2. A coil of insulated wire covered around a metallic piece when carrying current behaves as a magnet. The electromagnet is a temporary magnet formed as a result of the magnetic effect of an electric current. When current runs through the wires, it acts like a magnet. Electromagnets satisfy all the characteristics of an ideal magnet, such as

1. i) Attraction 
2. ii) Repulsion

iii) Directing towards north-south directions when hanging freely.

Electromagnets are of great use; they are extensively used in many devices. They can be made very strong and are even used in cranes to lift heavy loads from one place to another. 

Question 3. A nearby compass needle gets deflected from its north-south position when the current is switched on through a wire. Explain.

Answer 3. When current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position because magnetic fields are generated around it when the electricity passes through a metallic wire. These magnetic fields move the needle in north-south directions, creating deflection in the compass needle. 

Question 4. Fill in the blanks-

(a) Longer lines in the symbol for a cell represent its———— terminal.

(b) A combination of two or more two cells is known as————.

(c) When the current is switched ‘on’ in a room heater, it————.

(d) The safety device which is based on the heating effect of electric current is called a————-.

Answer 4. (a) Longer line in the symbol for a cell represents its Positive terminal.

(b) A combination of two or more cells is known as Battery.

(c) When the current is switched ‘on’ in a room heater, it produces heat.

(d) The safety device, which is based on the heating effect of electric current, is called a fuse.

Question 5. Mark’ True’ if the statement is true and ‘False’ if false-

(a) To make a battery of 2 cells, the negative end of one cell is connected to the negative end of the other. (T/F)

(b) When the Electric Current through the fuse crosses a specific limit, the fuse wire melts and breaks. (T/F)

(c) Electromagnet does not attract a piece of iron. (T/F)

(d) Electric bell has an electromagnet. (T/F)

Answer 5. i) False

1. ii) True

iii) False

1. iv) True

Question 6. Do you think that an electromagnet can be used to separate plastic bags from a heap of garbage?  

Answer 6. Since plastics do not possess magnetic properties, they do not get attracted to the magnet; therefore, an electromagnet cannot be used to carry out plastic bags or polythenes from a garbage heap.

Question 7. Which of the following safety measures need not be taken while using electronic gadgets/appliances/circuits?

(a) We should never touch a lighted electric bulb connected

to the mains.

(b) We should never experiment with the electric supply from

the mains or generator or an inverter.

(c) We should never use just any wire or strip of metal in

place of the fuse.

(d) We should never turn the switch on position.

Answer 7. The correct answer is Option (d). We should not turn the switch on position.

 Reason- for using any electronic gadgets/appliances/ circuit, we should first turn the switch off; hence option d is right. 

Question 8. How does the magnetic effect of electric current help in the working of the electric bell? 

Answer 8. An electric bell is made of a coil of wire wound on an iron piece. This coil now acts as an electromagnet. A small iron strip with a hammer attached at one end is kept close to the coil electromagnet. There is a screw near the iron strip. When the iron strip is connected with the screw, the current flows through the coil, which becomes an electromagnet. It then pulls the iron strip. The hammer hits the gong whenever the circuit is completed, which results in the ringing of the bell.

Question 9. Why do we cover plug pin holes which are within reach of children with cellotape or a plastic cover when not in use?

Answer 9. We should cover plug pin holes within reach of children with cellotape or a plastic cover when not in use because the children may put their finger in the open socket, which can cause severe electric shock which can be fatal. 

Question 10. Name two electric devices for each where (i) the heating effect of current is used and (ii) the magnetic effect of current is used.

Answer 10. i) heating effect is used in the heater, geyser etc.

1. ii) magnetic effect is used in cranes and electric bells.

Question 11. Write in brief about the heating effects of electric current.

Answer 11. When current flows through a metallic wire, the wire gets heated up; this is called the heating effect of current. For example, a glowing electric bulb becomes hot. This effect has many uses like electric heaters, geysers, etc.

Question 12. Describe the magnetic effects of electric current.

Answer 12 When an electric current flows through a wire, it produces magnetic effects around it. An electric current carrying a coil of an insulated wire wrapped around a piece of iron metal is called an electromagnet. The magnetic Effect of electric current has many applications in our daily life such as Electric bells, motors, fans etc. are all examples of the magnetic effect of electric current. 

 Question 13. State the factors upon which the force experienced by a current-carrying conductor placed in a uniform magnetic field depends.

Answer 13. Following are the factors which govern the force experienced by a conductor which is placed in a uniform magnetic field –

1. i) Strength of the magnetic field in which the conductor is placed.

1. ii) Strength of the electric current flowing through the conductor.

iii) Length of the conductor. 

Question 14. What are the characteristics of magnetic field lines?

Answer 14. Following are the characteristics of magnetic field lines:

1. i) These lines represent the magnetic field.

ii)These are directed from North to South Pole outside a magnet and from south to North Pole inside a magnet.

iii)The magnetic field lines are in a closed curve.

1. iv) Strength of the magnetic field in an area is determined by the closeness of the field lines in that area.

v)The closer the magnetic field lines are, the greater will be their field strength and vice–versa.

1. vi) No two magnetic field lines ever cross each other as it would mean two different directions of the field at the point of intersection, which is not possible.

vii) The parallel lines represent the uniform magnetic field, whereas converging lines or diverging lines represent the non-uniform magnetic field.

Question 15. What do you mean by electromagnetic induction?

Answer 15. The process by which a changing magnetic field in a conductor induces a current in another conductor is called electromagnetic induction.

Question 16. What are the filaments of a bulb and a heater made up of?

Answer 16. In a bulb, there is a very thin wire called the metallic filament made up of tungsten. When current passes through this wire, it glows and gets heated up. In a heater, a coil of wire is called an element which is made up of nichrome. When an electric current passes through an element, it becomes red hot and gives out heat.

Question 17. Write the principle of working electric generators. What are its important parts?

Answer 17. The working of electric generators is based on the principle of electromagnetic induction. The Important parts of electric generators are armature, slip rings, brushes and field magnets.

Question 18. Describe the patterns of magnetic field lines inside and outside of a solenoid. 

Answer 18. Following patterns of magnetic field lines inner and outside of a solenoid-

1. i) Magnetic field lines on the inside of the solenoid are parallel straight lines 
2. ii) The field lines outside the solenoid are curved lines

Benefits of Solving Class 7 Science Chapter 14 Important Questions

Science requires a lot of practice. Classes 6, 7 and 8 are crucial for students to develop a solid fundamental knowledge of the basic concepts of Physics, Chemistry and Biology. We recommend students access Extramarks comprehensive set of Important Questions Class 7 Science Chapter 14. By regularly solving questions and going through our answer solutions, students will get to know the key concepts applied to various devices. Also, students can identify their weak areas in Chapter 14, Electric Current and its Effects.

Following are some benefits of frequently solving electric current and its effects class 7 important questions:

• Our science experts have carefully collected the most important questions by analysing many past years’  question papers. So students will get exposure to actual exam questions while solving questions from our question bank.
• These questions and answers are based on the latest CBSE syllabus and as per CBSE guidelines. So students can rely on them fully.
• The questions covered in our set of Important Questions in Class 7 Science Chapter 14 are based on various topics covered in Chapter 14, Electric Current and its Effects. So while solving these questions, students can revise the entire chapter and clear any doubts they may have.
• Practising these types of questions based on the latest examination pattern would help students perform better in their exams and score good marks. 

At Extramarks, we understand the importance of revision notes and we take our role seriously to provide the best resource to the students and help them excel in life.  It provides comprehensive learning solutions for students from Class 1 to Class 12. We have abundant resources available on our website, along with essential questions and answers. Students can see the links given below to access some of these resources:

• NCERT books
• CBSE Revision Notes
• CBSE sample papers
• CBSE past years’ question papers
• Important formulas 
• CBSE extra questions