The wavelength of a photon that has an energy of 5.25 × 10-19 j is m.

The wavelength of a photon that has an energy of 5.25 × 10-19 j is 3.78 × 10-⁷m

HOW TO CALCULATE WAVELENGTH:

E = h × c/λ

Where;

The wavelength of the photon can be calculated as follows:

λ = hc/E

λ = (6.626 × 10-³⁴ × 3 × 10⁸) ÷ 5.25 × 10-¹⁹

λ = 19.878 × 10-²⁶ ÷ 5.25 × 10-¹⁹

λ = 3.78 × 10-⁷m

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  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-