Kaushal Bodh Class 8 Chapter 4 Extra Questions MCQ Working with Wood and Bamboo - #NCSOLVE 📚

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Working with Wood and Bamboo Class 8 Extra Questions MCQ

Working with Wood and Bamboo Class 8 Extra Questions

Question 1.
Define automation.
Answer:
Automation is the use of technology to control everyday devices automatically without manual intervention.

Question 2.
Name three examples of automation in homes.
Answer:
The three examples of automation in homes are
(i) Motion sensor lights
(ii) Automatic thermostat control
(iii) Automatic irrigation systems

Question 3.
What is the function of a microcontroller?
Answer:
A microcontroller processes signals from sensors and makes decisions to control output devices based on programmed logic.

Question 4.
Why should DC batteries be used instead of AC mains in educational circuits?
Answer:
DC batteries are safe as they provide low voltage (5 V-12 V), while AC mains (230 V) is dangerous and can cause serious harm.

Question 5.
What is an actuator?
Answer:
An actuator is an output device that performs an action in response to signals from the controller (for examples, motor, LED, buzzer and pump).

Question 6.
Name the three components of an automation system.
Answer:
The three components of an automation system are
(i) Input (sensor)
(ii) Process (controller)
(iii) Output (actuator)

Question 7.
What is the advantage of using a relay in a circuit?
Answer:
A relay allows a low-power circuit to control high-power devices safely, protecting the microcontroller from damage.

Question 8.
Describe the working principle of a motion sensor light system.
Answer:
A motion sensor light system works as follows

• The PIR sensor detects infrared radiation emitted by moving people. When motion is detected, it sends a signal to the microcontroller.
• The microcontroller processes this signal and activates the LED light.
• The light remains on for a set duration and automatically turns off after that period if no new motion is detected. This saves energy and provides convenience.

Question 9.
What are the safety precautions to be taken while working with electronic circuits?
Answer:
The safety precautions to be taken while working with electronic circuits are as follows

• Always use DC batteries or safe power adapters, never AC mains.
• Check all connections before switching on the circuit.
• Wear safety goggles while soldering.
• Handle soldering irons carefully to avoid burns.
• Keep the workspace clean and organised.
• Use proper tools for stripping wires.
• Never touch circuits with wet hands.
• Ask for help if unsure about any step.

Question 10.
How do automatic garden irrigation systems work?
Answer:
An automatic irrigation system uses a moisture sensor placed in the soil. When the soil becomes dry, the moisture level drops below a set threshold. This signal is sent to the microcontroller, which then activates the water pump.
The pump supplies water to the plants. As the soil becomes moist and reaches the desired moisture level, the sensor sends this information back to the controller, which turns off the pump. This cycle repeats automatically, ensuring plants receive water only when needed.

Question 11.
Explain why automation is found in nature. Give examples.
Answer:
Automation is round in nature because living organisms use automatic processes to survive without conscious effort. Examples include

• Heartbeat and breathing happen automatically in humans without thinking.
• The water cycle – water evaporates, forms clouds and rains continuously.
• Birds migrate to warmer regions without GPS guidance.
• Flowers bloom at the right season following natural signals.

Question 12.
What are the advantages of home automation systems?
Answer:
The main advantages of home automation are as follows

• Energy Saving Devices operate only when needed.
• Cost Reduction Lower electricity and water bills.
• Increased Comfort Automatic temperature control and lighting.
• Safety Security systems and emergency alerts.
• Convenience Hands-free control of appliances.

Question 13.
How do temperature sensors help in creating a smart thermostat system?
Answer:
Temperature sensors help in creating a smart thermostat system in the following ways

• A temperature sensor continuously measures the room temperature and sends signals to the microcontroller.
• The microcontroller processes the data and compares it with the set temperature value.
• It automatically switches heating or cooling devices ON or OFF based on need.
• This helps maintain a comfortable temperature and saves energy by reducing unnecessary power usage.

Question 14.
Compare manual control versus automatic control systems and discuss why automation is beneficial.
Answer:
Comparison of manual control and automatic control systems are

Aspect	Manual Control	Automatic Control
Definition	Tasks are performed by a person.	Tasks are performed automatically by a system.
Examples	Manually switching lights, watering plants by hand.	Motion sensor lights, automatic irrigation systems.
Human Effort	Requires constant human effort.	Requires little or no human effort.
Efficiency	Less efficient and time-consuming.	More efficient and saves time.
Consistency	Results may vary.	Gives consistent results.

Automation is beneficial because of the following reasons
(i) It saves time and reduces human effort by performing tasks automatically.
(ii) It improves efficiency and accuracy by ensuring consistent and timely operation of devices.

Question 15.
Explain the journey of automation from ancient times to modern smart cities, with specific examples.
Answer:
The journey of automation from ancient times to modern smart cities can be explained as follows: Ancient to Industrial Evolution

• Automation began with water clocks and sundials in 3000 BCE, followed by mechanical clocks using gears.
• The Industrial Revolution introduced the Jacquard Loom, which used punched cards to automate complex weaving patterns.
• Steam engines used governors to automatically regulate speed, marking a major shift in mechanical control.

Modern to Smart Cities

• Microprocessors enabled automated home appliances like washing machines, while remote controls added further convenience.
• Today, smart cities use AI and IoT for automated traffic control and efficient waste management.

Question 16.
Explain the Input-Process-Output (IPO) model along with its advantages.
Answer:
The Input-Process-Output (IPO) model is a basic framework used in automation systems to explain how a system works. In this model, the input is the information or signal received from sensors, such as a soil moisture sensor detecting dryness.
The process is carried out by a microcontroller, which analyses the input data and makes decisions based on programmed instructions.
The output is the final action performed by devices like a water pump, LED, or motor based on the decision.

Advantages of the IPO model are as follows

• It makes it easy to understand how an automation system works step by step.
• It helps in designing efficient systems by clearly separating input, processing, and output functions for better control and troubleshooting.

Question 17.
Explain how you would design a smart home security system and what sensors and components would be required.
Answer:
A smart home security system can be designed in the following ways

• Select a microcontroller such as Arduino or Raspberry Pi as the main control unit.
• Plan the system to monitor doors, windows and entry points for intrusions.
• Connect sensors and output devices to the microcontroller using proper circuit design.
• Write and upload a program that defines system actions for different inputs.

Sensors and Components Required

• PIR motion sensors to detect movement of people.
• Magnetic reed switches to monitor opening and closing of doors and windows.
• Camera module for visual monitoring.
• Buzzer for alarm system.
• LED indicators for system status.
• WiFi or GSM module for sending alerts.
• Relay module for controlling high-power devices.
• Power supply or backup battery for continuous operation.

Question 17.
Aman notices that the lights in his school corridor turn on automatically whenever someone walks by. Which device detects the movement and sends information to the automation system? What is this device called?
Answer:
This device is called a sensor. A sensor detects physical changes in the environment, such as motion, temperature or light, and converts them into electrical signals.

Question 18.
During a school electronics activity, students are asked to build and test a circuit using LED, resistor and battery. Instead of soldering the components permanently, the teacher gives them a board where components can be easily inserted, changed, and reused while testing the circuit. What is the role of this board in circuit prototyping?
Answer:
The role of a breadboard in circuit prototyping can be explained as follows

• It allows electronic components to be connected easily without soldering, making circuit building simple and safe.
• It helps in quickly testing and modifying circuits during the learning process.
• It supports identification and correction of errors before final soldering.
• It is reusable, so components can be removed and reused in other circuits for experimentation and practice.

Question 19.
In a school project, students are asked to design an automatic room light system that turns ON when a person enters and turns OFF when no motion is detected. They are given components like a sensor, microcontroller, LED, breadboard and wires. They must first test the circuit and then make it permanent. Describe the complete process they should follow to build and test this automation system along with appropriate safety measures.
Answer:
The complete process of building and testing an automation system with appropriate safety measures is
Process

• First, define the problem and select suitable sensors, microcontroller and output devices.
• Next, design the circuit and connect components on a breadboard carefully.
• Write and upload the program to the microcontroller using a computer.
• Test the system step by step and check whether inputs and outputs are working correctly.
• Finally, assemble the circuit permanently on a PCB and enclose it safely.

Safety Measures

• Use only a low-voltage DC power supply (5 V-12 V) instead of AC mains.
• Check all connections and polarity before switching ON the circuit.
• Wear safety goggles and use proper tools while soldering.
• Keep the workspace clean and avoid touching circuits with wet hands.

Question 20.
Answer the following questions based on the concepts represented in the diagram/images from this chapter.

(a) Which sensor is used in a motion sensor light system to detect movement?
(b) What happens in the process stage when the sensor detects motion?
(c) What is the output in a motion sensor light system?
Answer:
(i) The PIR (Passive Infrared Sensor) is used to detect movement in motor senser light system.
(ii) In the process stage, the microcontroller receives the signal from the PIR sensor, analyses it using programmed instructions, and decides to switch the LED light ON when motion is detected.
(iii) The output in a motion sensor light system is the LED light. It turns ON when motion is detected by the sensor and turns OFF after a set time delay automatically.

Question 21.
Answer the following questions based on the concepts represented in diagram/images from this chapter.

(a) Which component acts as the input device in the Arduino temperature sensing circuit?
(b) What is the function of the Arduino in the circuit?
(c) Which component gives the output in the temperature sensing circuit?
Answer:
(i) The temperature sensor acts as the input device in the Arduino temperature sensing circuit. It detects temperature changes in the environment and sends the corresponding signals to the microcontroller for processing.
(ii) The Arduino acts as the microcontroller in the circuit. It receives input from the temperature sensor, processes the data using programmed instructions, and controls the output device based on the results.
(iii) The LED is the output component in the temperature sensing circuit. It provides visual indication by turning ON or OFF based on the temperature data processed by the Arduino microcontroller.

Question 22.
Complete the following flow chart related to the Automation Cycle.

Answer:
(a) Input
(b) Processing

Question 23.
Complete the following flow chart related to Safety Precautions in Electronics.

Answer:
(a) Soldering precautions
(b) Workplace

Question 24.
Draw a concept map showing the main components of a home automation system.
Answer:

Question 25.
Make a concept map showing the role of a microcontroller in automation.
Answer:

Working with Wood and Bamboo Class 8 MCQ

Question 1.
What is automation?
(a) Using technology to control devices manually every time
(b) Using technology to control devices automatically without manual switching
(c) A completely new invention of modern times
(d) Only used in industries, not in homes
Answer:
(b) Using technology to control devices automatically without manual switching

Question 2.
Which component detects physical changes in the environment?
(a) Microcontroller
(b) Sensor
(c) Actuator
(d) Display
Answer:
(b) Sensor

Question 3.
What is the function of a microcontroller in an automation system?
(a) To supply power to the circuit
(b) To make decisions based on sensor inputs and control outputs
(c) To convert light into electrical signals
(d) To display information on a screen
Answer:
(b) To make decisions based on sensor inputs and control outputs

Question 4.
Riya is sitting quietly and notices that she is breathing normally without consciously thinking about it. Her heart is also continuously pumping blood throughout her body. Which type of automation does this example represent?
(a) Human-made automation
(b) Mechanical automation
(c) Automation in nature
(d) Computer-controlled automation
Answer:
(c) Automation in nature

Question 5.
What does PIR sensor stand for?
(a) Power Infrared Relay
(b) Passive Infrared Radiation
(c) Programming Integrated Response
(d) Precision Integrated Resistor
Answer:
(b) Passive Infrared Radiation

Question 6.
Which device is used to convert analog signals from sensors into digital signals?
(a) Transformer
(b) Amplifier
(c) ADC (Analog to Digital Converter)
(d) Inductor
Answer:
(c) ADC (Analog to Digital Converter)

Question 7.
What is the main advantage of home automation?
(a) It requires more manual work
(b) It saves energy, reduces costs and increases comfort
(c) It makes homes expensive
(d) It reduces the use of electricity
Answer:
(b) It saves energy, reduces costs and increases comfort

Question 8.
Which of these is not a component of an automation system?
(a) Input (Sensor)
(b) Process (Controller)
(c) Output (Actuator)
(d) Storage (Database)
Answer:
(d) Storage (Database)

Question 9.
What is the purpose of a relay in an automation circuit?
(a) To increase voltage
(b) To switch high-power devices using low-power signals
(c) To reduce current flow
(d) To measure temperature
Answer:
(b) To switch high-power devices using low-power signals

Question 10.
Which sensor is used to detect temperature changes?
(a) Light Dependent Resistor (LDR)
(b) Temperature Sensor (e.g., DHT11, LM35)
(c) Pressure Sensor
(d) Proximity Sensor
Answer:
(b) Temperature Sensor (e.g., DHT11, LM35)

Question 11.
During a history lesson on the evolution of automation, students learned about an ancient device that measured time automatically using the flow of water. Which device was it?
(a) Mobile phone
(b) Water clock
(c) Computer
(d) Television
Answer:
(b) Water clock

Question 12.
What is the main role of the breadboard in circuit building?
(a) To store electrical components
(b) To connect and test components without soldering
(c) To measure electrical current
(d) To power the circuit
Answer:
(b) To connect and test components without soldering

Question 13.
Which voltage supply is safe for educational electronics projects?
(a) 230 V AC (home supply)
(b) DC power from batteries (5 V-12 V)
(c) High voltage transformer
(d) Industrial AC supply
Answer:
(b) DC power from batteries (5V-12 V)

Question 14.
What does IoT stand for in the context of modern automation?
(a) Input Output Terminal
(b) Internet of Things
(c) Integrated Operating Technology
(d) Industrial Optimisation Tool
Answer:
(b) Internet of Things

Question 15.
Which component acts as an output device in an automation system?
(a) Sensor
(b) Microcontroller
(c) Actuator (Motor, LED, Buzzer, Pump)
(d) Power supply
Answer:
(c) Actuator (Motor, LED, Buzzer, Pump)

Fill in the Blanks

1. A __________ is a device that detects changes in the physical environment.
Answer:
Sensor

2. The __________ is the ‘brain’ of an automation system that makes decisions.
Answer:
Microcontroller

3. Home automation systems help in saving __________ and reducing costs.
Answer:
Energy

4. A __________ converts signals from sensors into digital information for the microcontroller.
Answer:
ADC (Analog to Digital Converter)

5. The three main components of an automation system are input __________ and output.
Answer:
Process (or Controller/Decision-making)

6. __________ is a board that allows components to be connected without soldering.
Answer:
Breadboard

True or False

1. Automation is a completely new concept invented in the 21st century.
Answer:
False

2. A motion sensor light requires manual switching on and off.
Answer:
False

3. It is safe to connect educational circuits directly to 230V AC mains.
Answer:
False

4. A relay is used to switch high-power devices using low-power signals.
Answer:
True

5. Sensors and human sense organs work in exactly the same way.
Answer:
False

The post Kaushal Bodh Class 8 Chapter 4 Extra Questions MCQ Working with Wood and Bamboo appeared first on Learn CBSE.

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