CBSE Class 10 Science Magnetic Effects of Electric Current VBQs Set 04

A & R Questions

Question. Assertion : When current is represented by a straight line, the magnetic field will be circular.
Reason : According to Fleming's left hand rule, direction of force is parallel to the magnetic field.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Answer: (c) Assertion is correct statement but reason is wrong statement.

Question. Assertion : Magnetic field is not associated with a stationary charge.
Reason : A magnetic field is detected by means of its effect on a current carrying conductor.
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Answer: (b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.

Multiple Choice Questions

Question. Magnetic field is produced by the flow of electric current in a straight wire. This phenomenon was discovered by
(a) Coulomb
(b) Oersted
(c) Faraday
(d) Maxwell
Answer: (b) Oersted

Question. A soft iron bar is introduced inside a current carrying solenoid. The magnetic field inside the solenoid
(a) will increase
(b) will remain unaffected
(c) will become zero
(d) will decrease
Answer: (a) will increase

Question. When the main switch of the house circuit is put off, it disconnects the
(a) earth wire
(b) live and neutral wires
(c) live wire
(d) neutral wire
Answer: (b) live and neutral wires

Question. When a fuse is rated 8 A, it means
(a) it will work only if current is 8 A
(b) it will burn if current exceeds 8 A
(c) it will not work if current is less than 8 A
(d) it has a resistance of 8 ohm
Answer: (b) it will burn if current exceeds 8 A

Question. When a magnetic compass needle is carried nearby to a straight wire carrying current, then
(I) the straight wire causes a noticeable deflection in the compass needle.
(II) the alignment of the needle is tangential to an imaginary circle with straight wire as its centre and has a plane perpendicular to the wire
(a) (I) is correct
(b) (II) is correct
(c) both (I) and (II) are correct
(d) neither (I) nor (II) is correct
Answer: (c) both (I) and (II) are correct

VSA Type Questions

Question. What are the two ways in which you can trace the magnetic field pattern of a bar magnet?
Answer: The two ways are: (i) By using iron filings. (ii) By using a magnetic compass needle.

Question. Magnetic field on the left side of a straight current-carrying wire is pointed upward. What will be the direction of the magnetic field on its right side?
Answer: The direction of the magnetic field on the right side will be pointed downward (into the plane).

Question. Where is the magnetic field due to current through a circular loop uniform?
Answer: The magnetic field is uniform at the centre of the circular loop.

Question. What is the electric potential of the neutral wire in main supply cable?
Answer: The electric potential of the neutral wire is zero volt.

Question. State the effect of a magnetic field on the path of a moving charged particle.
Answer: A magnetic field exerts a force on a moving charged particle, which causes it to move in a curved or circular path, provided its velocity is not parallel to the magnetic field.

SA I Type Questions

Question. (a) What is meant by magnetic field?
(b) State the effect of a magnetic field on the path of a moving charged particle.
Answer: (a) The region surrounding a magnet or a current-carrying conductor in which its magnetic influence can be detected is called a magnetic field.
(b) A magnetic field deflects a moving charged particle from its straight path, forcing it into a curved trajectory.

Question. Describe an activity to show how can you make an electromagnet in your school laboratory.
Answer: Take a large iron nail and wrap a long piece of insulated copper wire around it many times to form a coil. Connect the free ends of the wire to the terminals of a battery through a switch. When the switch is turned on, the nail becomes magnetised and can pick up small iron clips. When the switch is turned off, it loses its magnetism. This assembly is an electromagnet.