Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
(a) How should the electric lamps in a building be connected so that switching on or off in a room has no effect on other lamps in the building? State one more advantage of such an arrangement.
(b) Which effect of current is utilised in the working of an electric fuse? How does an electric fuse work?
(c) What is the usual colour of the insulation of (i) earth wire, and (1) live wire?
(d) When does an electric short circuit occur? What harm can it do? (e) Explain the purpose of earthing an electrical appliance.
(a) The electric lamps in a building should be connected in parallel connection so that the switching on or off in a room has no effect on other lamps in the same building.
The advantage of such an arrangement is that, if the devices in the circuit break down or no longer work, they will not affect other devices.
(b) Heating effect of current is utilized in the working of an electric fuse.
The electric fuse is designed to transmit only a certain amount (or, safe value) of current. Thus, if the current exceeds a safe value, the wire melts and breaks the circuit or discontinues the flow of current so that our household electrical equipment remains safe.
(c) The usual colour of the insulation of-
(i) earth wire $-$ green, or green-yellow.
(ii) live wire $-$ brown.
Image is posted for reference only
(d) Short-circuiting occurs when the plastic insulation of live and neutral wires gets torn somehow and touches each other, then due to this direct touching (connection) of the two wires an electric short circuit occurs.
In this case, the resistance of the circuit so formed is very small and therefore, the current flowing through the wires increases heavily, which can damage low power devices.
Image is posted for reference only
(e) The main purpose of earthing an electrical appliance is to avoid the risk of an electric shock. Earthing means connecting the metal case (or metal body) of an electrical appliance to the earth (at zero potential) through a metal wire called 'Earth Wire'. Metallic bodies of electric appliances such as refrigerators, electric irons, televisions are connected to the earth wire so that when any fault occurs or the live wire touches the metallic body the charge flows to the earth without damaging the appliance and without causing any injury to the humans.
Image is posted for reference only
50 Views
