It just is because science is science and it's supposed to make sense
I think the correct answer is C
Answer:
Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
Molarity (concentration) can be calculated by the equation:
Concentration = moles / volume in L = 0.54 mol / 0.6 L = 0.9 M
Hope this helps!
The unit 'mW' means milliwatts. It is a unit of work. There are 1,000 milliwatts in a 1 Watt of work. In 4 hours, there are 14,400 seconds.
Work= Energy/time
17 mW * 1 W/1000 mW = Energy/(14,400 seconds)
Solving for energy,
Energy = 244.8 J
Energy/photon = 244.8 J/(6.04×10²⁰) = 4.053×10⁻¹⁹ J/photon
Using the Planck's equation:
E = hc/λ
where h = 6.626×10⁻³⁴ m²·kg/s, c = 3,00,000,000 m/s and λ is the wavelength
4.053×10⁻¹⁹ J/photon = (6.626×10⁻³⁴ m²·kg/s)(3,00,000,000 m/s)/λ
λ = 4.9×10⁻⁷ m or 49 micrometers
