2. Which substances are used for making electromagnets?
3. Write a note on ‘ magnetic field’.
4. Why is a magnetic needle used in a compass?
5. Explain with the help of a diagram how the intensity and direction of the
magnetic field of a bar magnet can be determined.
Answers
Answer:
electromagnet: A magnet made of an insulated wire coiled around an iron core (or any magnetic material such as iron, steel, nickel, cobalt) with electric current flowing through it to produce magnetism. The electric current magnetizes the core material.
Question: Which substances are used for making electromagnets?
Ans: Electromagnet is made using – an iron nail, a long conducting copper wire about 1 meter, a battery and pins and can be tested.
Question: Write a note on ‘ magnetic field’.
Ans: ❖ Michael Faraday proposed the idea of magnetic lines of force to explain the magnetic field.
❖ The magnetism of a magnet acts upon a certain distance from the magnet.
❖ The space around the magnet in which the magnetic force acts on an object, is called a magnetic field.
❖ The magnetic field around the magnet can be shown with magnetic lines of force.
Question: Why is a magnetic needle used in a compass?
Ans: ❖ The magnetic needle used in a compass freely rotates and always settles in the north-south direction as it is a property of a magnet
❖ Thus, a magnetic needle can be used to ascertain the direction.
Hence, magnetic needle is used in a compass.
Question: Explain with the help of a diagram how the intensity and direction of the magnetic field of a bar magnet can be determined.
Diagram: Attached :)
Ans: ❖ The intensity of magnetic field is indicated by the magnetic lines of force in that particular area.
❖ Intensity of magnetic field in a particular area can be understood by the number of field lines passing perpendicular through that unit area.
❖ The intensity of magnetic field is more where the lines of force are more concentrated.
❖ The direction of magnetic field is determined by the directions of magnetic lines of force.
❖ The magnetic lines of force always start from the north pole and end on the south pole.
❖ In the similar manner, the direction of magnetic field is form north pole to south pole.
