9th Physics 2025 Chapter 8 Magnetism Short Questions
9th Physics 2025 Chapter 8 Magnetism Short Questions Notes. Class 9th Physics 2025 Chapter 8 Magnetism Short Question Answer.
Short Answer Question.
8.1 What are temporary and permanent magnets?
Temporary magnets are materials that act like a magnet only when they are placed in a strong magnetic field. Its example is soft iron.
Permanent magnets are materials that keep their magnetism for a long time even when the external magnetic field is removed. Its example is bar magnet.
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8.2 Define magnetic field of a magnet.
A magnetic field is the region around a magnet where another magnetic object experiences a force on it.
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8.3 What are magnetic lines of force?
Magnetic lines of force are imaginary lines. We use magnetic field lines to show the direction and strength of a magnetic field. These lines always show from the north pole to the south pole out side the magnet.
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8.4 Name some uses of permanent magnets and electromagnets.
People use permanent magnets in electric motors, electric generators and moving coil loudspeakers. People use electromagnets in electric bells, circuit breakers, and telephone receivers.
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8.5 What are magnetic domains?
Magnetic domains are small regions inside a magnetic material where the tiny magnetic fields of atoms are all lined up in the same direction. Each domain acts like a tiny magnet.
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8.6 Which type of magnetic field is formed by a current-carrying long coil?
A current-carrying long coil, also called solenoid, forms a uniform magnetic field inside it. These field lines will be parallel and equally spaced.
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8.7 Differentiate between paramagnetic and diamagnetic materials.
Paramagnetic materials weekly attracts magnets. They slightly increase the magnetic field. They have some unpaired electrons. Examples of paramagnetic materials are Aluminium and Platinum.
Diamagnetic materials weekly repels magnets. They slightly decrease the magnetic field. All electrons will be paired in diamagnetic materials. Examples of diamagnetic materials are Copper and Bismuth.
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