Free Download of Step-by-Step Solutions for Class 10 Physics Chapter 9 – Household Circuits of ICSE Board (Concise – Selina Publishers).
FAQs on Household Circuits Solutions for Class 10 Physics ICSE Board (Concise - Selina Publishers)
1. Describe two scenarios in which an electric device could cause an electric shock. What precautions must be included with the device to avoid this?
An electrical device can cause an electric shock in the following situations.If the fuse is placed in the neutral wire, an excessive current flows in the circuit due to a defect in the appliance, the fuse burns, and the current stops flowing in the circuit. However, the appliance is still connected to the high potential point of the supply via the live wire. In situations like this, touching the faulty item can be dangerous for people, he will receive an electric shock because the person will come into contact with the mains via the live wire.
As a precaution, the fuse must always be connected to the live wire. When the live wire of a faulty appliance comes into direct contact with its metallic case due to insulation failure after prolonged use, the appliance acquires the live wire's high potential. A person who comes into contact with the appliance will receive a fatal shock because current flows through his body to the earth. Preventive measure: The electric appliance should be properly 'earthed.'
2. Why must an earth wire be installed in a power circuit but not in a lighting circuit?
An earth wire must be installed in a power circuit because the power circuit transports high-power and expensive devices. If there is an unwanted power signal in the wire, it can damage the device. Earth wire is required to reduce this effect and cause less damage to anything. Students can refer to the Household Circuits Solutions for Class 10 Physics ICSE Board every year regularly(Concise - Selina Publishers) for more details and in depth solutions on this topic to study better.
3. Which wire is an electric appliance's metallic case connected to? What is the reason?
When the live wire of a faulty appliance comes into direct contact with its metallic case for whatever reason, the appliance acquires the live wire's high potential. A person who comes into contact with the appliance will receive a fatal shock because current flows through his body to the earth. However, if the appliance is properly earthed, a large current flows to the earth through the appliance's case as soon as the live wire comes into contact with it. The fuse connected to the appliance's circuit blows. As a result, the appliance is disconnected from the power supply.
4. What exactly do you mean by "local earthing"? Describe how it is done.
Local earthing is performed in the home near the kWh meter. A nearly 2 – 3 meter deep hole is dug in the ground for this purpose. In the hole is inserted a copper rod covered by a hollow insulating pipe. A thick copper plate 50 cm in size is welded to the lower end of the copper rod and buried underground. To ensure good contact between the plate and the earth, it is surrounded by a mixture of charcoal and salt.
Water is poured through the pipe on a regular basis to keep the ground moist. Between the plate and the ground, this creates a conducting layer. The upper end of the copper rod is connected to the kWh meter's earth connection.
5. Connecting the switch to the neutral wire is dangerous. Explain your response.
In the event of an overcurrent, connecting the switch to the neutral wire is very dangerous. Due to the excessive current, the fuse blows and the current in the circuit ceases to flow. However, the appliance is still connected to the high potential point of the supply via the live wire. If the person touches the body of the appliance, he will now receive an electric shock. As a result, using a fuse in the neutral wire is extremely dangerous.