Magnetic Effects of Electric Current: 10 Science

Question: A square coil moves in a plane with uniform velocity v parallel to its sides. A magnetic field B points perpendicular and into the loop. What is the induced current in the coil?

Answer: Zero, as there is no change in magnetic flux.

Question: A magnet is moved towards a coil, an emf and charge is induced in it. If the magnet is moved slowly, how will the new emf and charge be affected?

Answer: Emf will decreases without any change in the charge.

Question: A beam of alpha particles enter a chamber moving along a magnetic field. What is the magnetic force experienced by the beam?

Answer: Zero, as the beam is moving parallel ti the magnetic field.

Question: How does a current carrying solenoid behave?

Answer: It behaves like a bar magnet.

Question: When is the force experienced by a current carrying conductor placed in a magnetic field the largest?

Answer: When the current in the conductor flows perpendicular to the applied magnetic field.

Question: How is the induced current in a secondary coil related to current in a primary coil?

Answer: It may be greater than or less than the current in the primary coil.

Question: What is the pattern of field lines inside a solenoid? What do they indicate?

Answer: The field is in the form of parallel lines. It indicates a uniform magnetic field.

Question: How is the magnetic field produced in a solenoid used?

Answer: It is used to magnetize a soft iron piece to form an electromagnet.

Question: What does the direction of thumb indicate in the right-hand thumb rule?

Answer: The thumb indicates the director held by curled fingers.

Question: Mention the angle between a current carrying conductor and magnetic field for which the force experienced by this current carrying conductor placed in magnetic field is largest?

Answer: The angle is 90°

Question: Suggest one way of discriminating a wire carrying current from a wire carrying no current.

Answer: Bring a magnetic needle near the wire. A current carrying wire will produce a deflection in the needle whereas a wire without current will not.

Question: What does the thumb indicated in Fleming’s right hand rule?

Answer: It indicates the direction of motion of conductor.

Question: Why are magnetic field lines closed curves?

Answer: It is taken by convention that field lines emerge from North Pole and merge at the South Pole. Inside the magnet, the direction of field lines is from South Pole to North Pole, thus, magnetic field lines are closed curves.

Question: Write any one method to induce current in a coil.

Answer: By moving a magnet towards a coil.

Question: State two ways by which the strength of an electromagnet can be increased.

Answer: The strength of an electromagnet can be increased by:

1. Increasing the number of turns in the solenoid.
2. Increasing the strength of current flowing through the solenoid.

Question: Define a solenoid. How is it different from a coil?

Answer:

1. A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid.
2. The strength of magnetic field inside a coil vary while is case of solenoid, it is the same.