540 nm is the answer ! can you help me out please ? it is a science question add me and message me :)
Hawking was the first to set out a theory of cosmology explained by a union of the general theory of relativity and quantum mechanics.
Answer:
1.9×10^20
Explanation:
ϕ = number of reaction events /number of photons absorbed
ϕ= 0.26
Energy= power× time
885×10^-3×10×60= 531J
But E= nhc/λ
n= number of photons
h= planks constant
c= speed of light
λ= wavelength
n= Eλ/hc
n= 531×280×10^-9/6.6×10^-34 ×3×10^8
n= 7.5×10^20
Therefore
From
ϕ = number of reaction events /number of photons absorbed
Number of reaction events= 0.26×7.5×10^20
= 1.95×10^20
Answer is: the compound is B₂O₃.
ω(O) = 68.94% ÷ 100%.
ω(O) = 0.6894; percentage of oxygen in the compound.
ω(X) = 31.06% ÷ 100%.
ω(X) = 0.3106; percentage of unknown element in the compound.
If we take 69.7 grams of the compound:
M(compound) = 69.7 g/mol.
n(compound) = 69.7 g ÷ 69.7 g/mol.
n(compound) = 1 mol.
n(O) = (69.7 g · 0.6894) ÷ 16 g/mol.
n(O) = 3 mol.
M(compound) = n(O) · M(O) + n(X) · M(X).
n(X) = 1 mol ⇒ M(X) = 21.7 g/mol; there is no element with this molecular weight.
n(X) = 2 mol ⇒ M(X) = 10.85 g/mol; this element is boron (B).