How strong would a beam of light from a torch have 2 be 2 reach the moon and what type of battery do you need?
Answers:
If you shine a small flashlight in the direction of the moon in clear weather, most of the photons emitted by that flashlight will get to the moon. Someone with a really big telescope (10 km across) on the moon could see the flash from your flashlight.
If you want the photons to bounce off the moon and back to your eyes, you're going to need a bigger flashlight.
most torches run on gas not electric.
many double a battery.
It would have to be a laser of some sort I think. That's how they measure distances to the moon.
http://abcnews.go.com/technology/story?i.
really strong
think you'd be looking at running it from a nuclear power station rather than a battery, the bulb would have to be huge too as the filament would be huge to take that power without melting "aka blowing the bulb"
the same strenght i would have to be to go from the moon to the earth.
batteries? i would suggest a nuclear power plant.
2 AA batteries would do. The point is because you would get no reflected light back, you wont know that your beam(although not much of it) is actually on the moon. This is something that needs to be checked. Mainly by going to the moon.
Cosmos has got it. Some photons will get there regardless of the strength of your flashlight (Americans don't call it a torch).
So, it really depends what you want to do. If you wanted to light up the dark bit when the moon is crescent, you might need something gargantuan.
If you can get to see the thin crescent moon from a really dark place, you can often see the dark bit of the moon just glowing very faintly. I live rurally and often see this. It is actually sunlight reflected off the Earth and back to the moon.
The point is this is a massive amount of light by human standards reaching the moon via the Earth. If that is only just visible to us, and most people who live in cities have never seen it, just think what power you would need in your flashlight to enable you to see it shining on the moon's surface.
N.A.S.A has bounced a laser off a special mirror on the moon.
If you shone a torch beam to the moon, by the time it gets there the beam of light would be several hundred miles wide. The torchlight would not travel in a straight line like a laser
At least an AA battery
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