Answer: a) 
b) 
Explanation: Visible light is a form of electromagnetic wave.
Wavelength is defined as the distance between two successive crests of a wave. It is represented as symbol 
.
Frequency is defined as the number of complete cycles happening per second. It is represented by the symbol 
.
Wavelength and Frequency follow inverse relation,
where, c = speed of light = 
Wavelength and frequency of a wave is usually expressed in a range.
a) 
b) 
Explanation:
Each atom type contains the same number of protons. Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds
Answer:
pH = 4.9
Explanation:
Given data
[H⁺] = 13 × 10⁻⁶ M
The pH is a scale used to determine <em>the acidity or basicity of a solution</em>. The pH is related to the concentration of hydrogen ions through the following expression.
pH = -log [H⁺]
pH = -log 13 × 10⁻⁶
pH = 4.9
Since the pH < 7, the soil is considered to be acid.
