Electricity class 10 questions

Electricity class 10 questions (part 2)

1. The resistance of the conductor is R. If its length is doubled, then its new resistance will be  (a)R b) 2R (c) 4R (d) 8R
2. A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances 1 2 3 R R ,   and  R  respectively as shown in the figure. Which of the following is live?
3. The nature of the graph between potential difference and the electric current flowing through a conductor is  (a)parabolic  (b) circle  (c)  straight line    (d)  hyperbolic
4. Define the term “volt”?
5. Why does the connecting rod of an electric heater not glow while the heating element does?
6. n resistors each of resistance R are first connected in series and then in parallel.
7. What is the ratio of the total effective resistance of the circuit is series combination and parallel combination? 
8. (i) Out of these two wires which wire has higher resistance. (ii) Which wire has higher electrical Resistivity?  Justify your answer.
9. Two resistors of resistances R and 2R are connected in series is an electrical circuit?   Calculate the ratio of the electric power consumed by R and 2R?
10. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then in parallel in an electric circuit. the ratio of heat produced in series and parallel combinations would be (a) 1:2 (b) 2:1 (c)1:4 (d)4:1
11. What is the unit of resistance?      
12. The potential difference between the terminals of an electrical iron is 240 V and the current is  5.0 A. What is resistance of the electric iron? 
13. Why do we copper wires as connecting wires?  
14. What is the S.I. unit of electric power?
15. How many joules are in one watt-hour?