Magnetic effect of current Worksheet-11

Magnetic effect of current Worksheet-11

 

  1. What constitutes the field of a magnet ?

 

  1. What is the advantage of the third wire of earth connection in domestic appliances ?

 

  1. How can you show that the magnetic field produced by a given electric current in the wire decreases as the distance from the wire decreases ?

 

  1. When is the force experienced by a current-carrying conductor placed in a magnet field the largest ?

 

  1. Define the term induced current.

 

  1. How is the induced current in a secondary coil related to current in a primary coil ?

 

  1. What is meant by the term 'magnetic field' ? Why does a compass needle show deflection when brought near a magnet ?

 

True / False:

  1. An electric motor converts mechanical energy into electrical energy.

 

  1. An electric generator works on the principle of electromagnetic induction.

 

  1. The field at the centre of a long circular coil carrying current will be parallel straight lines.

 

  1. A wire with a green insulation is usually the live wire.

 

Answer:

  1. The space around a magnet within which its magnetic effect can be experienced constitutes the (magnetic) field of the magnet.

 

  1. In case of a defect in any domestic appliance, current leaks. The third wire of earth connection transfers this current to the earth. As a result of this, the user of the appliance is protected from the electric shock.

 

  1. If we take a magnetic compass slowly away from the current-carrying conductor, the deflection of the compass decreases. This shows that the magnetic field decreases as we move away from the current-carrying conductor.

 

  1. The maximum force is experienced by a current-carrying conductor only when it is perpendicular to the direction of magnetic field in which it is placed.

 

  1. The current set up in a closed circuit due to change of magnetic flux in it is called the induced current.

 

  1. A changing current in a primary coil sets up an induced current in the secondary coil.

 

  1. (i) The space around a magnet in which the force of attraction and repulsion due to the magnet can be detected is called the magnetic field.

(ii) The compass needle shows deflection (when brought near a magnet) due to magnetic force exerted on it by the magnet.

 

True / False:

  1. False

Explanation: An electric motor converts electric energy into mechanical energy.

 

  1. True

 

  1. True

 

  1. False

Explanation: wire with a green insulation is usually the earth wire.