- AAc only
- BDc only
- CEither ac or dc
- DNeither dc nor ac
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A heater of 220 V heats a volume of water in 5 minute time. A heater of 110 V heats the same volume of water in
|
(a) 5 minutes |
(b) 8 minutes |
(c) 10 minutes |
(d) 20 minutes |
A slit of width a is illuminated by white light. For red light (λ = 6500 Å), the first minima is obtained at θ = 30°. Then the value of a will be
|
(a) 3250 Å |
(b) 6.5 |
(c) 1.24 microns |
(d) 2.6 |

Focal length of a convex lens will be maximum for
|
(a) Blue light |
(b) Yellow light |
(c) Green light |
(d) Red light |
A TV tower has a height of 100 m. The average population density around the tower is 1000 per km2. The radius of the earth is 6.4 m. the population covered by the tower is
|
(a) 2 |
(b) 3 |
(c) 4 |
(d) 6 |