Answer : The wavelength of photon is, 
Explanation : Given,
Energy of photon = 
Formula used :
As, 
So, 
where,
= frequency of photon
h = Planck's constant = 
= wavelength of photon = ?
c = speed of light = 
Now put all the given values in the above formula, we get:
Conversion used : 
Therefore, the wavelength of photon is,
Heat supplied to the gold will raise the temperature of the gold from 20 degree Celsius to 90 degree Celsius.
Mass of the gold (m) = 0.072 kg
Temperature change (ΔT) = 90 - 20 = 70 degree Celsius
Specific heat capacity of the gold (c) = 136 J/kg C
Heat supplied = m × c × ΔT
Heat supplied = 0.072 × 136 × 70
Heat supplied = 685.44 Joules
Hence, the heat supplied to the gold to raise the temperature from 20 degree Celsius to 90 degree Celsius = 685.44 Joules
<span>Exothermic reaction is a chemical reaction that releases energy. This reaction releases heat energy or light .
In an endotermic reaction energy is used.
Enthaply is the heat energy change , delta H.
If the sum of the enthalpies of the reactans is greater than the products the reaction is exothermic. If the products side has a larger enthaply than the process is endothermic. So, if delta H is negative then the process is exothermic. If delta H is positive, than the process is endothermic.
Exothermic are: A+BC -> AB+C
A2+B2 -> 2AB
Endothermic are:AB+C -> AC+B
A2 + C2 -> 2AC
B2+C2 -> 2BC</span>
A mirror is opaque you can not see through it but you can see a reflection within it
