Answer:
3.025eV
Explanation:
Energy of a photon is given by
E=hν
Where h is the Planck's constant
And ν represents the frequency of the photon .
Now for violet light wavelength λ=410nm= 410x10^-9m
By using the formula ν=c/λ
where c represents speed of light I.e 3 x 10^8 m/s
Calculating energy of violet photon we have
E=hc/λ
h=6.626 x 10^-34 J.s
On inserting the value in the formula , we get
E= 4.848 x 10^-19 Joules
To convert it into electron volts we need to divide it by 1.602 x10^-19.
The final result what we have is E=3.026eV.
Note: the result calculated is according to the above value . result may vary according to the values taken .
The pH of pure water is neutral because the concentration of hydronium ions equals that of hydroxide ions.
Answer: Option A
<u>Explanation:</u>
Water is one of the most important constituents of living being. It is said that there is no life without water. So that water need to neutral in nature to save life. Pure water is composed of hydronium
and hydroxide
ions. It is known that hydronium ions are acidic in nature with concentration of
.
Similarly, the hydroxide ions which are basic in nature will be in same concentration as that of hydronium ions. So, as the concentration of basic and acidic elements are equal with the same strength of pH, the combination of these ions lead to formation of pure water with the pH being neutral.