Answer
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Hint
Electric current is made up of moving charges that tend to produce magnetic fields due to the generation of magnetic dipoles. This generated magnetic field also exerts a force on nearby charges. This property can be used to our benefit in many ways.
Complete step by step answer
Let us see what the different electrical applications mentioned in the question are based on:
An electric bulb uses the principle of heat generation in the filament due to electricity, and hence no magnetic effect is used. A geyser also uses the heat effect as the heating rod increases in temperature and causes the water surrounding it to boil slowly. The effect of thermodynamics is used here.
As the name suggests, an electromagnet generates a magnetic field around it when current starts flowing through it. It is made by using coils made of current-carrying wire. The more tightly wound the coil is, the stronger is the magnetic field produced.
An electric motor makes use of this electromagnet to generate a magnetic field that is ultimately used to generate mechanical energy from electrical input.
Hence, the answers are option (A) and (C).
Note
A current carrying wire tends to create a magnetic field around it. This effect was observed by Oersted who saw a compass deflect when brought near a current carrying wire. He also noticed that the compass only gets deflected when brought into a certain range of the wire. Upon changing the direction of current flow in the wire, he noticed that the compass deflected on the opposite side too. And that is how the magnetic effect of electric current was discovered.
Electric current is made up of moving charges that tend to produce magnetic fields due to the generation of magnetic dipoles. This generated magnetic field also exerts a force on nearby charges. This property can be used to our benefit in many ways.
Complete step by step answer
Let us see what the different electrical applications mentioned in the question are based on:
An electric bulb uses the principle of heat generation in the filament due to electricity, and hence no magnetic effect is used. A geyser also uses the heat effect as the heating rod increases in temperature and causes the water surrounding it to boil slowly. The effect of thermodynamics is used here.
As the name suggests, an electromagnet generates a magnetic field around it when current starts flowing through it. It is made by using coils made of current-carrying wire. The more tightly wound the coil is, the stronger is the magnetic field produced.
An electric motor makes use of this electromagnet to generate a magnetic field that is ultimately used to generate mechanical energy from electrical input.
Hence, the answers are option (A) and (C).
Note
A current carrying wire tends to create a magnetic field around it. This effect was observed by Oersted who saw a compass deflect when brought near a current carrying wire. He also noticed that the compass only gets deflected when brought into a certain range of the wire. Upon changing the direction of current flow in the wire, he noticed that the compass deflected on the opposite side too. And that is how the magnetic effect of electric current was discovered.