The flow of the Chang Jiang is some 20 times greater than that of the
Huang He. As much of 40% of China's total grain production, 70% of rice
output, and more than 40% of the population are associated with the
Chang Jiang's vast basin that includes more than 3,000 tributaries. With
its numerous tributaries, the Chang Jiang drains nearly 20% of China's
total area. Its upper reaches tap the uplands of the Tibetan Plateau
before sweeping across the enormous and agriculturally productive
Sichuan Basin that supports nearly 10% of China's total population. It
is in the middle course of the Chang Jiang that the controversial Three
Gorges Dam is being constructed.
Answer:
d). It is easier to make a large reflecting telescope than a large refracting telescope.
f). A reflector can collect more light than a refractor.
Explanation:
A telescope is a device that is used to observe distant objects by the use of lenses and mirrors. It is also used to observe different distant objects by their reflection, absorption, emission or the reflection of the electromagnetic radiations.
Most of the professional telescopes are reflectors because :
1. The reflected telescope is able to receive more of the light when it reflects all the light falling on surface. And it is easier for making a large telescope rather then making large lenses for the refracting telescope. So it is easier to make large reflecting telescope than a large refracting telescope.
2. A reflected telescope receives all the wavelength of the light and it reflects all the light falling on the surfaces where it is refracted telescope that contains lenses cannot absorbs all the light and causes the chromatic aberration.
