The unit for measuring the rate at which light is radiated from a source is B, Lumen. Lumenous flux is the time rate of the flow of light, or the visible energy produced from a certain light source. It is the quantitative measure of brilliance of a light source. The unit we use for this is lumen.
Formula: PE = mgh
m = 20 kg, g = 9.8 m/s^2 h= ?
1000 = 20 * 9.8 * h
1000 = 196h
h = 5.10204082
The height is around 5m
Answer:
We can use optical fibers.
Explanation:
The optical fibers are the optical devices which is based on the total internal reflection.
The optical fiber has two layers, one is called core and the other is called cladding.
The refractive index of core is more than the cladding.
As a ray of light falls on the core at more than the critical angle for that pair of media(core and cladding), it suffers the total internal reflection at the interface.
I think they can use more durable materials.