Saturday, October 25, 2008

Q n A - 1

1) This is w.r.t the image on ur blog. See the image, the reflection of the turtle is seen on the water surface. How is this possible considering light is reflected of the surface.
Ans: first the light enters from top of water to the turtle's skin, gets reflected/scattered and reaches to the water surface. Now when it is approaching from below, it gets totally internally reflected...

2) In a laptop screen only for certain viewing angles of the monitor, can the images be seen clearly. At other angles the images cannot be see. Why is this sp.
Ans: The laptop's pixels are like little torches, made up of a substance called liquid crystals. These send light, like a torch, in a cone shaped beam. so if you are out of the beam angle, then you don't see a good image!

3) People say if only google webpage had a black background, then so much electricity would be saved. How?
Ans: The white and other colors need electricity to switch on the little torches on the computer screen pixels. The black color is just absence of any light at all. So showing a black background would save electricity in general. particularly, since millions of visitors use the google page daily, it will save lot of energy.

4) A car requires a 12 volt DC battery. These batteries are huge. I have 8 1.5 volt AA size batteries. Can i connect them in series and replace the car battery.
Ans:- Lets see what a battery is. It has chemicals that keep the positive and negative charges piled up with some distance in between them. Now the voltage depends on how much charge can be piled up, and current on how fast this charge can be transfered. a small 1.5 volt battery can't withstand a fast moving charge flow, as needed in a car. A car battery has a high current rating, e.g. to give the ignition spark. So in case of batteries, the current rating is important along with the voltage.

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