The correct option is D.
Sound proofing is usually achieved by using materials that absorbed or reduce sounds. Different materials are used in sounding proofing and these differ in their abilities to absorb or reduce sounds. The coefficient of absorption of a material refers to that material ability to absorb sound. The higher the percentage of a material absorption coefficient, the better the material's ability to absorb sound. Thus, in the question given above, the material with 62% absorption coefficient have the greatest ability of the three materials to absorb sound effectively. <span />
Answer:
o The result of a chemical change is a different composition; in a physical change, the composition remains the same.
Explanation:
In a chemical change, new kinds of matter are produced although the atoms are the same.
For physical changes, no new kinds of matter formed. Only the state of substances changes.
- Most chemical changes are usually irreversible
- Physical changes are reversible in most parts.
- Changes in state and form are salient characteristics of physical changes.
- When new products are formed from the reactants, it is an indicator of a chemical change.
Cell phones may be radioactive.Maybe this is the reason???.
