Thermal energy travels<span> by conduction, convection, and radiation. It occurs when a cooler and warmer object touches each other. </span>
Reaction 3 is the double displacement reaction.
Double displacement reaction occurs when the negatively and the positively charged ions of the compounds interchange their position when the new compound in the product is formed.
<h3>Which is a double displacement reaction?</h3>
In the <u>first reaction</u>, the element lead (Pb) is not an ion and no exchange of the cations or the anions occurs hence it is not a double displacement reaction.
In the <u>second reaction</u>, one compound is getting split into two new compounds and is a decomposition reaction.
In the <u>third reaction</u>,
in
and
in
are anions and cations and exchanges their places to produce two new compounds 
In the <u>fourth reaction</u>, a single compound is generated as the result of the combination reaction and hence, it is not the double displacement reaction.
Therefore,
is the double displacement reaction.
Learn more about double displacement reaction here:
brainly.com/question/10091171
Answer:
Light energy acts as a catalyst that speeds up the rate of photosynthesis
Explanation:
Where is the illustration?
Answer:
photons are emitted per second in a
Watt microwave oven.
Explanation:
The expression for the power is:-

Also, 
Where,
n = the number of photons
h = Plank's constant having value 
c = the speed of light having value 
= the wavelength of the light
So,

Thus, the expression for photons per second is:-

Given that:-
Power = 10³ Watt
( 1 cm = 0.01 m)
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So,

photons are emitted per second in a
Watt microwave oven.