Concave is not a type of mechanical wave because it doesn’t need a medium for propagation.
Answer:
B. as a food preservative in the manufacture of detergents
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If the results of the experiment on repeating are not same, it shows the results are not standard, there are some factors, which are not constant
Answer:
Because it can cause health problems or injuries to our sense organs.
Explanation:
Chemicals in the laboratory are made up of different constituents, which may be dangerous or injurious to health. This is the reason why safety measures or precautions have to be taken when working in the laboratory. One of those safety measures is that "one should never use taste, touch, or smell to identify an unknown chemical".
This is so because a chemical that is unknown amounts to the fact that what such chemical contains is unknown, hence, the chemical might have the ability to cause harm or injuries to the sense organ. For example, a conc. acid that is tasted will burn the tongue etc.
The increase in the number of atoms allows the strong positive charge of the nucleus to increase. Thus, due to the number of positive protons increasing in the nucleus, the positive charge increases. On the negatively charged electron cloud, the high positive charge of the nucleus has a strong tug.
