Table of Contents

9th Physics Chapter 8 Long questions

9th Physics Chapter 8 Long questions. We will answer only revised syllabus 9th class physics 2025.

8.1 How can you identify whether an object is a magnet or a magnetic material?

We can identify if an object is a magnet or a magnetic material with the help of repulsion test. We bring one end of the given object near a magnet. If the object repel the magnet, its a magnet. If it shows only attraction, its a magnet material.

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8.2 Describe the strength of a magnetic field in terms of magnetic lines of force. Explain it by drawing a few diagrams for the fields as examples.

Strength of magnetic field is described by the number of magnetic lines of forces passing through given area. These lines always go from North pole to South pole outside the magnet. The magnetic field is strong where the lines of force are close together and the magnetic field is weak where the lines of force are far apart.

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8.3 What is a circuit breaker? Describe its working with the help of a diagram.

Circuit breaker is a device which is used to an electric circuit by breaking the circuit whenever the current exceeds the safe limit.

When excess current flows, it produces a strong magnetic field in the electromagnet. This magnet field pulls the iron armature, causing the contacts to separate. Due to this, the circuit opens and current supply is cut off.

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8.4 A magnet attracts only a magnet. Explain the statement.

A magnet attracts only magnet is not a complete statement. Because a magnet can attract only magnet and magnetic material also. Magnwtic materials are not magnets themselves. Correct statement is that a magnet repels only a magnet.

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