MAGNETIC EFFECTS OF ELECTRIC CURRENT - II : BRIEF ANSWERS

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ANSWER IN BRIEF

1. Mention the advantages of alternating current(AC).
   

   ANS:The advantages of alternating current(AC) are:
   

   
   
   1. Alternating current is easy to produce.
      
   2. The production of AC is cheaper compared to that of DC.
      
   3. Electricity can be transmitted over longer distances without much loss.
      

   
   

   
   
   
2. Write the Right Hand Thumb Rule and show the diagram explaining it.
   

   ANS:
   
   
   Hold the conducting wire in the right hand such that the thumb is stretched along the direction of the current, then the fingers will wrap around the conductor in the direction of the magnetic field.
   

   
   
   
3. What are the disadvantages of using direct current (DC) ?
   

   ANS:
   The disadvantages of using direct current are:
   

   
   
   1. Its production is comparatively costlier than that of alternating current.
      
   2. The production and distribution of alternating current is easier than that of direct current.
      
   3. The distribution of direct current over long distances involves heavy loss of energy.
      

   
   

   
   
   
4. All domestic appliances are joined in parallel, why ?
   

   ANS:
   All domestic appliances are connected in parallel because :
   

   
   
   • In parallel connection all the appliances are connected between two common points.Therefore all have same voltage equal to that of line voltage across the terminals. Thus all appliances work smoothly with maximum efficiency.
     
   • If an appliance fails or stops due to some reason, the remaining appliances continue to operate because current is still passing through them. Thus, there is no interruption due to breakage of circuit.
     
   • Parallel connection of appliances reduces power loss because the resultant resistance is smaller than individual resistances.
     

   
   

   
   
   
5. Explain the importance of earthing wire (earthwire).
   

   ANS:
   

   
   
   • The earth wire connects the body of an appliance (like an iron or toaster) to the earth via a metal plate kept deep in the earth.
     
   • If due to some fault the live wire comes in contact with the body of the appliance, the earth wire sends the current from the body to the earth and the user gets protection against the possible electric shock.
     
   • Thus, earth wire is needed for the protection of the user.
     

   
   

   
   
   
6. What is the work of a fuse ?
   

   ANS:
   

   
   
   • Fuse is a metal wire having very low melting point and high resistance.
     
   • If due to some reason the current in the circuit increases suddenly, the fuse wire melts and breaks the circuit preventing the current from going further and passing through costly appliances like TV, freeze, etc.
     
   • Thus, costly appliances are protected and the probability of an accident and major damage is minimized.
     

   
   

   
   
   
7. Mention the characteristics of solenoid.
   

   ANS:

   
   
   • Solenoid behaves as a magnet when electric current is passed through the coil.
   • The magnetic field associated with a solenoid is n times stronger than the field due to one loop, if it has n turns in the coil.
   • The magnetic field is similar to that of a bar magnet,i.e., one end of the solenoid behaves as north pole and the other as south pole.
     

   
   

   
   
   
8. 
   

   ANS: