Answer:
"nonmetal, nonmetal"
Explanation:
Oxygen is a non metal and Nitrogen is a non metal. It is 8th element of the periodic table. It is located in period 2 and group 16.
Nitrogen lies at the group 15 of the periodic table. Its atomic no is 7. Its valency is 2.
Hence, the correct option is (c) "nonmetal, nonmetal".
<u>Answer:</u> The energy of one photon of the given light is 
<u>Explanation:</u>
To calculate the energy of one photon, we use Planck's equation, which is:

where,
= wavelength of light =
(Conversion factor:
)
h = Planck's constant = 
c = speed of light = 
Putting values in above equation, we get:

Hence, the energy of one photon of the given light is 
Scientists can measure the height in
different units but problem could arise when they compare all the measurements.
That is the reason there is standard units for measurements.
<span>There may be error arises when an
American scientist is measuring the height of an object in inches and other Australian
scientist is measuring the height of same object in meters. Their data cannot
be compared because they are using different units to measure height.</span>
Answer:
A combustion reaction is a reaction that involves a substance and oxygen reacts at high temperature and produces light energy and thermal energy and generate light and heat.
If a flame is in a sealed container it will go out due to the absence of oxygen to perform a combustion reaction that requires oxygen to produce heat and light. A flame is the result of a combustion reaction which also requires the oxygen to keep on burning.