Answer: an electromagnetic wave of a frequency between about 104 and 1011 or 1012 Hz, as used for long-distance communication.
Explanation:
Answer:
1.8g/cm³
Explanation:
Density is defined as the ratio of the mass of a substance and the space this subtance occupies. It is usually given in g/cm³.
The mass of the block is 30g.
The volume this mass occupies is 1.5cm × 4.8cm × 2.3cm = 16.56cm³.
The density is:
30g / 16.56cm³ =
<h3>1.8g/cm³</h3>
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The goal is to produce water fit for a specific purpose. Most water is disinfected for human consumption (drinking water), but water purification may also be designed for a variety of other purposes, including fulfilling the requirements of medical, pharmacological, chemical and industrial applications. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultra violet light.