Class X Physics
1.Why is much less heat generated in long electric cables than in filament of electric
bulb?
2.Which one has a higher resistance: a 100w bulb or a 25w bulb and how many times?
3.A geyser is rated 1500w,250v.The geyser is connected to 250v mains. Calculate (i) the
current drawn (ii)the energy consumed in 50hours (iii) the cost of energy consumed at
Rs2.20per kwh.
4.Why Nichrome alloy is used for making the heating element of electrical appliances?
5.A wire of resistance 5 ohm is bent in the form of a closed circle. What is the effective
resistance between the two points at ends of any diameter of a circle?
6.What will happen to the resistivity if we double the length of the wire?
7.Why does the sky appear dark instead of blue to an astronaut?
8.Why there is no dispersion of light refracted through a rectangular glass slab?