In vacuum, going at 2.99×10^8 m/s.
Answer:
D) Roger is incorrect. Only a chemical change is taking place as evidenced by the light and heat of the burning candles.
Explanation:
- A physical change is a change in which there is no formation of new substances. Examples of physical changes are the melting or the evaporation of a substance (all phase transitions are examples of physical changes): in such cases, there is no formation of new substances.
- A chemical change is a change in which new substances form. Examples of chemical changes are the chemical reactions: for instance, when a candle burns, a reaction is taken place (oxygen is burnt, transforming into carbon dioxide + heat + light, so this is an example of chemical change).
Therefore, the correct answer is
D) Roger is incorrect. Only a chemical change is taking place as evidenced by the light and heat of the burning candles.
Answer:
a structural variation in which different atoms of the same element have different numbers of neutrons
Explanation:
An isotope is an atom of an element having the same number of protons but different number of neutrons. Different isotopes are used for different purposes. Example: some are used in medicines , food irradiation, etc.
Carbon has three isotopes C 12, C 13, C 14. All three of them have 6 protons but have different numbers of neutrons.
C 12 is a common element and is abundant in nature
C 13 is less abundant than C 12
C 14 is used for dating fossils . It is radioactive
The wave nature of light, due to the experiment having bright and dark bands corresponding to places where you have constructive and destructive interference.
