Answer:
1. Previous Eye Surgery
.
Explanation:
1.
Your medical history can also affect your vulnerability to cataracts. For instance, a previous eye surgery can cause secondary cataracts. Other conditions including diabetes and excessive use of steroids accelerate the chances of cataracts once a person has already undergone previous eye surgeries.
Hertz is units for frequency. (waves per second)
wavelength = speed/frequency
if you're given the speed use that to calculate, if not then you can probably assume it's a wave of light and use the speed of light (3x10^8 m/s) to calculate.
wavelength = (3x10^8)/(1.28x10^17)
= 0.000000002 m
= 2.34 nm
Answer:
• Molecular mass of Iron (III) tetraoxide

[ molar masses: Fe → 56, O → 16 ]

The study of chemistry helps us understand the nature of the world around us. Chemistry is always developing to keep up with any phenomenon that appears in nature.
Therefore, scientists and chemists are always developing new technologies. However, chemists must very careful when developing these new technologies. They should consider any bad chemical reactions that might occur and also chemicals that harmful to either the individuals or the environment.
Answer: Calcium Sulphate Hemihydrate
The compound of calcium which is used for plastering of fractured bones is Plaster of Paris. It is also called as Calcium Sulphate Hemihydrate.