Table of Contents
Electric Current and its Effects- Worksheets
Hello Students,
Welcome to your worksheets on the chapter “Electric Current and Its Effects.” This chapter is a crucial part of your science studies, introducing you to the fundamentals of electricity and its various applications and effects in our daily lives.
In this chapter, you have learned about-
- Symbols of Electronic Components- Understanding the symbols used in electric circuits, such as cells, bulbs, and switches.
- Electric Circuit- Learning how an electric circuit is formed and the role of different components in making a bulb glow.
- Heating Effect of Electric Current- Exploring how electric current can heat a wire, leading to practical applications like electric heaters and irons.
- Magnetic Effect of Electric Current- Understanding how an electric current can turn a wire into a magnet and the creation of electromagnets.
- Electromagnet and its Uses- Learning about electromagnets and their various applications, including in devices like electric bells.
- Safety with Electricity- Emphasising the importance of safety while handling electrical devices and the use of fuses and MCBs (Miniature Circuit Breakers).
These worksheets include a variety of questions that will help you revise and consolidate your understanding of these topics. They are designed to test your knowledge and prepare you for your exams. By completing these worksheets, you will enhance your understanding of the important concepts of electric current and its effects.
Also Check- Rapid Revision – Class 7 Science- Chapter 14 – Electric Current and Its Effects
Worksheet 1 – Electric Current and its Effects – Student Worksheet (Unsolved)
Explain with Examples-
(a) What is the role of a switch in an electric circuit? Provide an example of how it is used in a household appliance.
(b) Discuss the heating effect of electric current with the example of a specific appliance.
True or False – Justify Your Answer-
(a) An electric fuse is used to increase the current flow in a circuit. (T/F)
(b) Rubber is a good conductor of electricity. (T/F)
Multiple Choice Questions-
(a) What is the primary purpose of an electric fuse in a household circuit?
(i) To control the light intensity
(ii) To prevent overloading
(iii) To increase voltage
(iv) To store electric charge
(b) Which material is generally used for making the filament of a bulb?
(i) Copper
(ii) Aluminium
(iii) Tungsten
(iv) Iron
Diagram-Based Question-
Draw and label a simple electric circuit containing a battery, a bulb, and a switch.
Discuss the Concept-
Discuss the concept of overloading in electric circuits and its potential risks.
Fill in the Blanks-
(a) A device that converts electrical energy into mechanical energy is known as a(n) __________.
(b) The __________ of a wire affects its ability to conduct electricity.
Scenario-Based Question-
If a household circuit keeps tripping, what could be the probable reasons, and how would you suggest resolving them?
Comparative Analysis-
Compare the use of traditional incandescent bulbs and CFLs in terms of energy efficiency and cost.
Practical Application-
Explain how electromagnets are used in everyday appliances or devices.
Discussion-Based Questions
Discuss the safety measures one should take while handling electrical appliances and the importance of using ISI-marked devices.
Also Check- Batteries- The Powerhouses of Everyday Life – A Guide for Upper Primary Students
Worksheet 1 – Electric Current and its Effects – Solved Worksheet with Answer
Explain with Examples-
(a) Role of a Switch in an Electric Circuit-
A switch is used to make or break the electric circuit, controlling the flow of current. For example, in a household lamp, the switch allows the user to turn the light on and off, thereby controlling the electrical connection to the lamp.
(b) Heating Effect of Electric Current-
The heating effect of electric current is used in appliances like electric irons. When electric current passes through the iron’s heating element, it generates heat, which is then used to iron clothes.
True or False – Justify Your Answer-
(a) An electric fuse is used to increase the current flow in a circuit. (F) – A fuse is used to prevent overloading by breaking the circuit if the current exceeds a safe level.
(b) Rubber is a good conductor of electricity. (F) – Rubber is an insulator and does not conduct electricity.
Multiple Choice Questions-
(a) Primary Purpose of an Electric Fuse-
Answer- (ii) To prevent overloading – Fuses protect circuits from damage due to excessive current.
(b) Material Used for Making the Filament of a Bulb-
Answer- (iii) Tungsten – Tungsten filament is used because of its high melting point and good emissivity.
Diagram-Based Question-
Simple Electric Circuit Diagram-
Draw a circuit including a battery (represented by a series of short and long parallel lines), a bulb (shown as a circle with a filament inside), and a switch (depicted as two dots connected by a line that can be opened or closed).
Discuss the Concept-
Overloading in Electric Circuits-
Overloading occurs when too many appliances are used simultaneously on a single circuit, drawing more current than the circuit can handle. This can lead to overheating and potentially cause fires. It’s important to distribute electrical devices across different circuits and use appropriate fuses or circuit breakers.
Fill in the Blanks-
(a) A device that converts electrical energy into mechanical energy is known as a(n) electric motor.
(b) The thickness (or gauge) of a wire affects its ability to conduct electricity.
Scenario-Based Question-
Tripping Household Circuit-
Probable reasons include circuit overloading, short-circuiting, or a faulty appliance. Solutions involve checking for and eliminating overloading, inspecting for any damaged wires or sockets, and ensuring all appliances are in good working condition.
Comparative Analysis-
Traditional Incandescent Bulbs vs. CFLs-
Incandescent bulbs are less energy-efficient and have a shorter lifespan compared to CFLs (Compact Fluorescent Lamps). CFLs use less electrical energy to produce the same amount of light and last longer, which can be more cost-effective despite a higher initial price.
Practical Application-
Use of Electromagnets in Everyday Appliances-
Electromagnets are widely used in devices like electric bells, where an electromagnet forms an integral part of the mechanism to produce sound. They are also used in hard drives to read and write data and in medical equipment like MRI machines.
Discussion-Based Questions
Safety Measures for Handling Electrical Appliances-
Important safety measures include not overloading sockets, using appliances with a proper grounding, avoiding the use of damaged cords or plugs, keeping appliances away from water, and using ISI-marked devices to ensure they meet safety standards.
Also Check – Electric Bell Working Mechanism Simplified for Students
Worksheet 2 – Electric Current and its Effects – Student Worksheet (Unsolved)
Conceptual Understanding-
(a) Define electric current and distinguish between alternating current (AC) and direct current (DC).
(b) Explain the role of a resistor in an electric circuit and how it influences the current flow.
Identify and Explain-
(a) Identify two common materials used as conductors and two as insulators. Explain the reason for their conductivity or resistance.
(b) Describe the concept of electric potential and its significance in an electric circuit.
True or False – Justify Your Answer-
(a) The brightness of a bulb is determined by the voltage applied to it. (T/F)
(b) All metals are good conductors of electricity. (T/F)
Multiple Choice Questions-
(a) What is the primary function of a fuse in an electric circuit?
(i) To regulate voltage
(ii) To increase current
(iii) To prevent overloading
(iv) To decrease resistance
(b) Which of these is not a characteristic of an ideal insulator?
(i) High melting point
(ii) High conductivity
(iii) Resistance to electric flow
(iv) Non-reactive to electricity
Diagram-Based Question-
Draw a diagram of a series circuit with one battery, two resistors, and a bulb. Label all components and show the direction of current flow.
Real-Life Application-
Discuss how understanding the magnetic effect of electric current has revolutionised the field of electromagnetics and its applications in various technologies.
Critical Thinking-
Evaluate the role of circuit breakers in household safety and compare them with fuses.
Fill in the Blanks-
(a) A device that converts mechanical energy into electrical energy is known as a(n) __________.
(b) The opposition that a material offers to the flow of electric current is called __________.
Scenario-Based Question-
If a household appliance starts drawing more current than it is designed for, what might be the potential risks, and how can they be mitigated?
Comparative Analysis-
Compare the advantages and disadvantages of using CFLs (Compact Fluorescent Lamps) over traditional incandescent bulbs.
Discussion-Based Questions
Discuss how the concept of resistance is crucial in designing any electronic or electrical device.
Also Check- Class 7 science -Chapter 14 – Electric Current and Its Effects- Complete Notes
Worksheet 2 – Electric Current and its Effects – Solved Worksheet with Answer
Conceptual Understanding-
(a) Definition and Distinction between AC and DC-
Electric current is the flow of electric charge, typically measured in amperes. Alternating Current (AC) changes direction periodically, while Direct Current (DC) flows in only one direction. AC is commonly used in power supplies, whereas DC is used in batteries and electronic devices.
(b) Role of a Resistor in an Electric Circuit-
A resistor is a component that opposes the flow of electric current, causing a reduction in current or a drop in voltage. It’s used to control the current in a circuit and can protect delicate components from excessive current.
Identify and Explain-
(a) Conductors and Insulators-
Conductors (e.g., Copper, Aluminum) allow electricity to flow easily due to the presence of free electrons. Insulators (e.g., Rubber, Glass) resist electric flow and are used to prevent unwanted flow of current.
(b) Electric Potential-
Electric potential is the work done to move a charge from one point to another in an electric field, measured in volts. It’s significant as it represents the potential energy per charge and influences the flow of charge in a circuit.
True or False – Justify Your Answer-
(a) The brightness of a bulb is determined by the voltage applied to it. (T) – Higher voltage increases the energy per charge, increasing the current and making the bulb brighter.
(b) All metals are good conductors of electricity. (F) – Most metals are good conductors, but there are exceptions based on atomic structure and electron availability.
Multiple Choice Questions-
(a) Primary Function of a Fuse-
Answer- (iii) To prevent overloading – A fuse melts when the current exceeds a certain limit, breaking the circuit and preventing potential damage.
(b) Not a Characteristic of an Ideal Insulator-
Answer- (ii) High conductivity – Conductivity is a characteristic of a conductor, not an insulator.
Diagram-Based Question-
Series Circuit Diagram-
Draw a series circuit with a battery at one end, followed by two resistors and a bulb in a line. Label each component and indicate the direction of current flow from the positive to the negative terminal of the battery.
Real-Life Application-
Magnetic Effect of Electric Current-
The magnetic effect of electric current is the basis of electromagnets, used in everything from electric motors and generators to maglev trains and MRI machines. Understanding this effect has been crucial in the development of numerous technologies.
Critical Thinking-
Role of Circuit Breakers vs. Fuses-
Circuit breakers and fuses both protect against excessive current, but circuit breakers can be reset and reused, offering more convenience and often more sensitivity. They are crucial for modern electrical safety in homes and industries.
Fill in the Blanks-
(a) A device that converts mechanical energy into electrical energy is known as a(n) generator.
(b) The opposition that a material offers to the flow of electric current is called resistance.
Scenario-Based Question-
Overcurrent in Household Appliance-
Risks include overheating, potential fires, or damage to the appliance. Mitigation involves using a proper rating of fuses, circuit breakers, and ensuring the appliance is maintained and not overloaded with power.
Comparative Analysis-
CFLs vs. Traditional Incandescent Bulbs-
CFLs are more energy-efficient and have a longer lifespan than incandescent bulbs, reducing long-term costs and environmental impact. However, they are more expensive upfront and contain small amounts of mercury which can be a concern if broken.
Discussion-Based Questions
Importance of Resistance in Device Design-
Understanding resistance is crucial for designing any electronic or electrical device to ensure it operates safely at the intended performance level. It helps in determining the specifications of components and the overall efficiency of the device.
Also Check- NCERT Solutions for Class 7 Science Chapter 14- Electric Current and its Effects
Worksheet 3 – Electric Current and its Effects – Student Worksheet (Unsolved)
Explain the Concepts-
(a) Describe how an electric circuit is formed and the role of each component in it.
(b) Explain the magnetic effect of electric current.
True or False – Justify Your Answer-
(a) An electric fuse is designed to protect appliances from high voltage. (T/F)
(b) CFL bulbs work on the principle of the heating effect of electric current. (T/F)
Multiple Choice Questions-
(a) What happens when the filament of an electric bulb breaks?
(i) The bulb emits more light.
(ii) The bulb’s circuit becomes incomplete.
(iii) The bulb consumes more electricity.
(iv) The bulb becomes a conductor.
(b) Which of the following is not an effect of electric current?
(i) Magnetic effect
(ii) Heating effect
(iii) Illuminating effect
(iv) Cooling effect
Diagram-Based Question-
Draw a simple circuit diagram that includes a battery, a resistor, and a bulb. Indicate the direction of the current.
Real-Life Application-
Discuss the importance of circuit breakers (MCBs) in household electrical safety.
Fill in the Blanks-
(a) A device that transforms electrical energy into light and heat is called a(n) __________.
(b) __________ is a safety device that prevents electrical overloads by melting under excessive current.
Critical Thinking-
How do the properties of the materials used in the filament of a bulb affect its functioning?
Practical Understanding-
Describe how an electric bell works using the principles of electromagnetism.
Comparative Analysis-
Compare the working principles and applications of electromagnets and permanent magnets.
Discussion-Based Questions
Discuss the significance of the ISI mark on electrical appliances.
Also Check- NCERT Exemplar Solutions- Class 7 Science- Chapter 14 – Electric Current and Its Effects
Worksheet 3 – Electric Current and its Effects – Solved Worksheet with Answer
Explain the Concepts-
(a) Formation of an Electric Circuit-
An electric circuit is formed by connecting electrical components in a loop, allowing current to flow. Key components include a power source (battery), conductors (wires), a resistor or load (like a bulb), and a control device (switch). The battery provides the energy, the wires conduct it, the resistor controls the flow, and the switch can open or close the circuit.
(b) Magnetic Effect of Electric Current-
When electric current flows through a conductor, it creates a magnetic field around it. This is known as the magnetic effect of electric current. This principle is used in devices like electromagnets, electric bells, and motors.
True or False – Justify Your Answer-
(a) An electric fuse is designed to protect appliances from high voltage. (F) – A fuse protects against excessive current, not voltage. It breaks the circuit if the current exceeds a safe limit.
(b) CFL bulbs work on the principle of the heating effect of electric current. (F) – CFLs work on the principle of the electric discharge through gas and not the heating effect of electric current.
Multiple Choice Questions-
(a) What happens when the filament of an electric bulb breaks?
Answer- (ii) The bulb’s circuit becomes incomplete – The filament breaking causes the circuit to open, stopping the flow of electricity and hence the bulb stops emitting light.
(b) Which of the following is not an effect of electric current?
Answer- (iv) Cooling effect – Electric current typically causes magnetic, heating, and illuminating effects but not a cooling effect.
Diagram-Based Question-
Simple Circuit Diagram-
Draw a battery with two terminals connected to a resistor and a bulb in series. The wire from the bulb then goes back to the other terminal of the battery. Indicate the direction of current from the positive to the negative terminal of the battery.
Real-Life Application-
Importance of Circuit Breakers-
Circuit breakers (MCBs) are crucial in household electrical safety as they automatically switch off the electrical circuit during abnormal conditions like overloads or faults. They help in preventing electrical fires and damage to appliances.
Fill in the Blanks-
(a) A device that transforms electrical energy into light and heat is called a(n) electric bulb.
(b) A fuse is a safety device that prevents electrical overloads by melting under excessive current.
Critical Thinking-
Properties of Materials in Bulb Filaments-
The filament material in a bulb, typically tungsten, is chosen for its high melting point and resistance. These properties allow the filament to heat up and emit light without melting, ensuring the bulb’s functionality and longevity.
Practical Understanding-
Working of an Electric Bell-
An electric bell uses electromagnetism. When activated, current flows through an electromagnet, creating a magnetic field that pulls a metal arm to strike a bell. When the arm moves, the circuit breaks, stopping the current and the magnetic field, causing the arm to return. This cycle repeats rapidly, creating a ringing sound.
Comparative Analysis-
Electromagnets vs. Permanent Magnets-
Electromagnets generate a magnetic field through electric current, and their strength can be adjusted. They’re used in devices like motors and speakers. Permanent magnets have a constant magnetic field but cannot be turned off or adjusted, used in compasses and fridge magnets.
Discussion-Based Questions
Significance of the ISI Mark-
The ISI mark on electrical appliances signifies that the product meets the Indian Standard for safety and quality. This assures consumers that the product is safe, reliable, and of good quality, reducing the risk of electrical hazards.
Also Check- Chapter 14- Electric Current and Its Effects-Class 7 science- Question and Answers
Worksheet 4 – Electric Current and its Effects – Student Worksheet (Unsolved)
Conceptual Questions-
(a) Describe the difference between a closed and an open electric circuit.
(b) Explain why an electric bulb glows when the electric circuit is closed.
Interpretation and Application-
(a) What happens to the brightness of a bulb if the filament inside it breaks, and why?
(b) Discuss how the design of a circuit diagram simplifies the understanding of an electric circuit’s functioning.
True or False – Justify Your Answer-
(a) Overloading in an electric circuit can cause the wires to become extremely hot. (T/F)
(b) A short circuit is typically caused by the separation of live and neutral wires. (T/F)
Multiple Choice Questions-
(a) What is the main function of a fuse in an electric circuit?
(i) To increase the flow of current
(ii) To prevent electric shocks
(iii) To prevent overloading and short circuits
(iv) To reduce the voltage
(b) Which of the following is a correct representation of a cell in a circuit diagram?
(i) A circle with a cross inside
(ii) A set of parallel lines with one line longer than the other
(iii) A rectangle
(iv) A zigzag line
Diagram-Based Question-
Draw a circuit diagram representing a parallel connection of two bulbs and a battery. Label all components.
Real-Life Application-
Explain the importance of using ISI-marked electrical appliances in households.
Fill in the Blanks-
(a) In an electric bell, an ___________ is used to make and break the circuit rapidly to produce a ringing sound.
(b) ___________ is a type of magnet where the magnetic field is produced by electric current.
Critical Analysis-
Compare the benefits and potential risks of using miniature circuit breakers (MCBs) over traditional fuses in household circuits.
Practical Understanding-
Describe the process of how a fuse operates in a circuit during an overload or short circuit.
Discussion-Based Questions
Discuss the effects of the heating effect of electric current and its practical applications in daily life.
Also Check- Chapter 14- Electric Current and Its Effects–Class 7 science- Question and Answer -(Solved MCQs)
Worksheet 4 – Electric Current and its Effects – Solved Worksheet with Answer
Conceptual Questions-
(a) Difference Between a Closed and an Open Electric Circuit-
In a closed circuit, the electrical path is complete, allowing current to flow. For example, when a switch is turned ON, it closes the circuit, enabling electricity to power a bulb or device. In contrast, an open circuit has a break in the path, typically when the switch is OFF, preventing the flow of electricity and hence, the bulb or device does not work.
(b) Electric Bulb Glowing in a Closed Circuit-
An electric bulb glows in a closed circuit because the closed path allows electric current to flow through the bulb’s filament. The filament, typically made of tungsten, offers resistance to the flow of electricity, heating up to a high temperature and emitting light as a result.
Interpretation and Application-
(a) Brightness of a Bulb if the Filament Breaks-
If the filament inside a bulb breaks, the circuit becomes incomplete, stopping the flow of electric current. Without current, the filament can’t heat up and emit light, so the bulb does not glow.
(b) Simplification of Circuit Diagrams-
Circuit diagrams simplify the understanding of electric circuits by using standardised symbols to represent various components. This abstraction allows for easy visualisation and interpretation of how components are connected and interact in the circuit without the complexity of physical details.
True or False – Justify Your Answer-
(a) Overloading in an electric circuit can cause the wires to become extremely hot. (T) – Overloading occurs when too much current flows through the wires, causing them to heat up due to their resistance, which can lead to melting of insulation or even fire hazards.
(b) A short circuit is typically caused by the separation of live and neutral wires. (F) – A short circuit usually occurs when the live and neutral wires come into direct contact, either due to damaged insulation or faulty wiring, causing a sudden increase in current flow.
Multiple Choice Questions-
(a) Main Function of a Fuse-
Answer- (iii) To prevent overloading and short circuits – Fuses protect circuits by breaking the connection if the current exceeds a safe level.
(b) Correct Representation of a Cell in a Circuit Diagram-
Answer- (ii) A set of parallel lines with one line longer than the other – This represents a cell with the longer line typically indicating the positive terminal.
Diagram-Based Question-
Parallel Circuit Diagram-
Draw a battery with two terminals. From one terminal, draw two parallel lines extending and then branching off into two separate loops, each with a bulb symbol (circle with a cross inside), before joining back and returning to the other terminal of the battery. This represents a parallel circuit with two bulbs connected to a single battery.
Real-Life Application-
Importance of Using ISI-Marked Electrical Appliances-
ISI-marked electrical appliances conform to the Indian Standards for safety and quality. Using these appliances ensures they are energy-efficient, safe, and reliable, reducing the risk of electrical hazards like short circuits or overheating.
Fill in the Blanks-
(a) In an electric bell, an electromagnet is used to make and break the circuit rapidly to produce a ringing sound.
(b) An electromagnet is a type of magnet where the magnetic field is produced by electric current.
Critical Analysis-
Benefits and Risks of Using MCBs over Fuses-
MCBs (Miniature Circuit Breakers) are more convenient than traditional fuses as they can be easily reset after tripping, unlike fuses which need to be replaced. MCBs provide better protection against overloading and short circuits. However, they are more expensive than fuses and may require professional installation.
Practical Understanding-
Operation of a Fuse in Overload or Short Circuit-
In an overload or short circuit, the current flowing through the circuit increases significantly. A fuse contains a metal wire that melts when the current exceeds a safe threshold, breaking the circuit and stopping the flow of electricity, thus preventing damage or fire hazards.
Discussion-Based Questions
Effects of the Heating Effect of Electric Current-
The heating effect of electric current is utilised in many household appliances like electric heaters, toasters, and irons, where electricity is converted into heat for practical use. This effect is also fundamental in incandescent bulbs, where the filament heats up to emit light. However, it can be a safety concern in wiring and devices if not properly managed, as excessive heating can lead to fire hazards.
Worksheet 5 – Electric Current and its Effects – Student Worksheet (Unsolved)
Understanding Basic Concepts-
(a) What are the main components of a simple electric circuit? Explain the function of each component.
(b) How do the properties of the wire in a circuit affect its overall performance?
Analysing Circuit Behavior-
(a) Describe what happens in a circuit if a switch is turned OFF. Why does this occur?
(b) Explain the significance of the arrangement of cells in a battery when connected in series vs parallel.
True or False – Justify Your Answer-
(a) CFL bulbs are less energy-efficient than incandescent bulbs. (T/F)
(b) An electromagnet loses its magnetism as soon as the electric current is switched off. (T/F)
Multiple Choice Questions-
(a) What does the ISI mark on an electrical appliance signify?
(i) It is imported
(ii) It is energy-efficient
(iii) It meets certain safety and quality standards
(iv) It is made of recyclable materials
(b) In an electric bell, what role does the electromagnet play?
(i) It rings the bell
(ii) It provides power
(iii) It makes and breaks the circuit
(iv) It controls the volume
Practical Application-
Explain how an electric fuse functions and why it is an essential safety component in household circuits.
Fill in the Blanks-
(a) A _________ is used in circuits to control the amount of current flowing through them.
(b) The _________ effect of electric current is utilised in devices like electric heaters and toasters.
Comparative Analysis-
Compare the advantages of using LED bulbs over traditional incandescent bulbs.
Scenario-Based Question-
If a household appliance begins to malfunction, producing a burning smell, what steps should be taken to address the issue?
Discussion-Based Questions
Discuss how advancements in electrical technology have impacted household appliances in terms of safety and efficiency.
Worksheet 5 – Electric Current and its Effects – Solved Worksheet with Answer
Understanding Basic Concepts-
(a) Main Components of a Simple Electric Circuit-
Power Source- Provides the necessary energy for the current, typically a battery or power supply.
Conductor- Usually wires made of materials like copper that allow current to flow easily.
Load/Resistor- A device that uses electricity, like a bulb or a resistor, which controls the flow of current.
Switch- A component that can open or close the circuit, controlling the flow of electricity.
(b) Properties of Wire in Circuit Performance-
The material, thickness, and length of the wire affect its resistance. Lower resistance (thicker, shorter wires of good conductors like copper) allows better current flow, whereas higher resistance (longer, thinner wires or wires made of poorer conductors) can limit current flow.
Analysing Circuit Behavior-
(a) What Happens When a Switch Is Turned OFF-
Turning OFF a switch opens the circuit, breaking the path of the electric current. This stops the flow of electricity, causing devices in the circuit (like a bulb) to stop working.
(b) Significance of Cell Arrangement-
In series, cells add their voltage, increasing the total voltage available to the circuit. In parallel, the voltage remains the same as a single cell, but the duration or capacity of the power supply increases.
True or False – Justify Your Answer-
(a) CFL bulbs are less energy-efficient than incandescent bulbs. (F) – CFLs are more energy-efficient than incandescent bulbs, consuming less electricity for the same amount of light.
(b) An electromagnet loses its magnetism as soon as the electric current is switched off. (T) – Electromagnets rely on electric current to generate a magnetic field, which disappears once the current is stopped.
Multiple Choice Questions-
(a) Significance of ISI Mark-
Answer- (iii) It meets certain safety and quality standards – ISI mark ensures the product adheres to the Indian Standard specifications.
(b) Role of Electromagnet in Electric Bell-
Answer- (iii) It makes and breaks the circuit – The electromagnet repeatedly attracts and releases a metal strip, causing the bell to ring.
Also Check- Electric Bell Diagram for Class 7 Science
Practical Application-
Function of an Electric Fuse-
A fuse is a safety device that protects circuits from excessive current. It contains a metal wire that melts when the current exceeds a specified limit, breaking the circuit and stopping the flow of electricity to prevent damage or fire.
Fill in the Blanks-
(a) A resistor is used in circuits to control the amount of current flowing through them.
(b) The heating effect of electric current is utilised in devices like electric heaters and toasters.
Comparative Analysis-
LED Bulbs vs. Incandescent Bulbs-
LED bulbs are more energy-efficient, have a longer lifespan, and are more environmentally friendly than incandescent bulbs. While LEDs have a higher upfront cost, they save more energy and money over time.
Scenario-Based Question-
Malfunctioning Appliance Producing a Burning Smell-
Immediately switch off and unplug the appliance. Check for any visible signs of damage or short circuits. It’s advisable to consult a professional electrician to inspect and repair the appliance to prevent potential hazards.
Discussion-Based Questions
Impact of Electrical Technology Advancements-
Advances in electrical technology have greatly improved safety and efficiency in household appliances. Modern appliances are equipped with better insulation, efficient energy usage, and safety features like automatic shut-offs and circuit breakers, reducing risks and enhancing functionality.
