EARTH SCIENCE
MAGNETISM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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They are weaker than permanent magnets.
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They can’t be turned off.
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They do not have magnetic fields.
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They can switch their magnetic poles.
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Detailed explanation-1: -D They are temporary magnets. Electromagnets are a special class of magnets with properties such as: The polarity of the magnets can be reversed by reversing the current flow. As long as electric current flows through them, they behave as magnets, i.e. they are temporary magnets and hence can be switched on and off.
Detailed explanation-2: -An electromagnet is a magnet that runs on electricity. Unlike a permanent magnet, the strength of an electromagnet can easily be changed by changing the amount of electric current that flows through it. The poles of an electromagnet can even be reversed by reversing the flow of electricity.
Detailed explanation-3: -The strength of an electromagnet can be changed by changing the number of turns in its coil and by increasing the current through it. Therefore option 3 is correct. As the electromagnet is a temporary magnetic which is only working till when we give the current to it.
Detailed explanation-4: -The magnetic poles always exist in pairs. It is not possible to separate the two poles of a magnet.
Detailed explanation-5: -The correct answer is Polarity cannot be changed.