Friday, November 6, 2015

ELECTRICITY TEST

Time:-1 hour            M.M.:-20
1.       Why is tungsten metal selected for making filaments of incandescent lamp bulbs?  (1)
2.       Relate kWh with joule?    (1)
3.       What are superconductors? Who invented it?  (2)
4.       How is the fuse wire connected? What is its advantage? (2)

5.       Classify materials into various kinds based on their conducting property? How are superconductors different from this?  (2)
6.       A wire of length l, area of cross section A and material of resistivity ρ is cut into two parts in the ratio 1:3 of length. Find the ratio of their (i)resistivity  and (ii)resistance.  (2)
7.       How much current will an electric heater rated 1 kW draw when connected to 250 V?  (2)
8.       You have 3 resistances of value R each. How will you connect these for obtaining a total resistance of 3R/2 ? Show this connection by a diagram?(2)
9.       A toaster produces more heat than a light bulb when connected in a parallel to the 220 V mains. Which of the two has greater resistance?  (3)
10.   Geyser draws a current of 15A from the main line for half an hour to heat water. Calculate the amount of charge that flows through the filament.   (3)




Time:-1 hour            M.M.:-20
1.       Why is tungsten metal selected for making filaments of incandescent lamp bulbs?  (1)
2.       Relate kWh with joule?    (1)
3.       What are superconductors? Who invented it?  (2)
4.       How is the fuse wire connected? What is its advantage? (2)
5.       Classify materials into various kinds based on their conducting property? How are superconductors different from this?  (2)
6.       A wire of length l, area of cross section A and material of resistivity ρ is cut into two parts in the ratio 1:3 of length. Find the ratio of their (i)resistivity  and (ii)resistance.  (2)
7.       How much current will an electric heater rated 1 kW draw when connected to 250 V?  (2)
8.       You have 3 resistances of value R each. How will you connect these for obtaining a total resistance of 3R/2 ? Show this connection by a diagram?(2)
9.       A toaster produces more heat than a light bulb when connected in a parallel to the 220 V mains. Which of the two has greater resistance?  (3)

10.   Geyser draws a current of 15A from the main line for half an hour to heat water. Calculate the amount of charge that flows through the filament.   (3)

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