Electromagnets are used in electric bells.<\/li>\n<\/ol>\nElectric Current and Its Effects Class 7 Extra Questions Short Answer Type 2<\/h3>\n Question 1. \nDiscuss the reason for excessive currents in electrical circuits. \nAnswer: \n(i) One reason for excessive currents in electrical circuits is the direct touching of wires. This may happen if the insulation on the wires has come off due to wear and tear. This may cause a short circuit. \n(ii) Another reason for excessive current can be the connection of many devices to a single socket. This may cause overload in the circuit.<\/p>\n
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Electric Current and Its Effects Class 7 Extra Questions Long Answer Type<\/h3>\n Question 1. \nWrite construction and working of an electric bell. \nAnswer: \nConstruction: It consists of a coil of wire wound on an iron piece. The coil acts as an electromagnet. An iron strip with a hammer at one end is kept close to the electromagnet. There is a contact screw near the iron strip.<\/p>\n
Working: When the iron strip is in contact with the screw, the current flows through the coil which becomes an electromagnet. It, then, pulls the iron strip. In the process, the hammer at the end of the strip strikes the gong of the bell to produce a sound. However, when the electromagnet pulls the iron strip, it breaks the circuit. The current through the coil stops flowing. \n <\/p>\n
The coil is now no longer an electromagnet. It no longer attracts the iron strip. The iron strip comes back to its original position and touches the contact screw again. This completes the circuit. The current flows in the coil and the hammer strikes the gong again. This process is repeated in quick succession. The hammer strikes the gong every time the circuit is completed. This is how the bell rings.<\/p>\n
Hope the knowledge provided regarding the Electric Current and Its Effects Class 7 Extra Questions and Answers has helped you to the possible extent. For more info feel free to reach us and we will guide you at the earliest possibility. Stay connected to our site to avail latest updates on Extra Questions for Various Classes instantly.<\/p>\n","protected":false},"excerpt":{"rendered":"
Electric Current and Its Effects Class 7 Extra Questions and Answers Science Chapter 14 PDF are solved by experts and will guide students in the right direction. Students can get how to tackle different questions easily by solving the Extra Questions for Class 7 Science Question bank on a regular basis. Class 7 Science Chapter …<\/p>\n
Electric Current and Its Effects Class 7 Extra Questions and Answers Science Chapter 14<\/span> Read More »<\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[9],"tags":[],"yoast_head":"\nElectric Current and Its Effects Class 7 Extra Questions and Answers Science Chapter 14 - NCERT Solutions<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n