TEST PAPER 18 : CHAPTER 4 : ELECTRICITY : 25 MARKS

There are 13 questions in all and time limit is 45 minutes.

SECTION - A : CHOOSE APPROPRIATE ALTERNATIVE : [1 mark each, Total marks 3]

1. When resistors are connected in series...
   
   
   
   1. voltage drop is uniform
   2. current is uniform
   3. both voltage and current are uniform
   4. neither of the two is uniform
      
   
   
2. 1 A = ______ mA.
   
   
   
   1. 100
   2. 1000
   3. 10^(-3)
   4. 10⁶
      
   
   
3. Equivalent resistance of resistances in parallel is...
   
   
   
   1. smaller than the smallest resistance
   2. greater than the greatest resistance
   3. an average of all resistances
   4. algebraic sum of all resistances
      
   
   

   SECTION - B : ANSWER IN SHORT : [1 mark each, Total marks 4]
   

4. What type of charge does a glass rod acquire when it is rubbed with silk cloth ?
5. Define : Electroplating.
6. Current flows in a wire. Can we call the wire charged ? Why ?
   
   

   SECTION - C : ANSWER IN BRIEF : [2 marks each, Total marks 6]
   

7. Mention two disadvantages of series connection.
8. Explain the cause of resistance in a conductor. What are conductors and insulators ?
9. Define electric power and write different equations of power.
10. A lamp of resistance 20 ohm is joined to a battery of 12 V. Find the value of the resistance to be connected in series with the lamp in order to get current of 0.5 A.
    
    

    SECTION - D : ANSWER THE FOLLOWING : [3 marks each, Total marks 6]
    

11. Define electric current and explain the difference of electron current and conventional current.
12. What is series connection? Derive the formula of equivalent resistance for three resistors connected in series.
    
    

    SECTION - E : ANSWER IN DETAIL : [5 marks each, Total marks 5]
    

13. Describe Ohm's experiment and write its conclusion.