Question

What is the energy
requirement of another energy
level from the energy level of -
3.7eV, if wavelength is 2.1 x 10-7
m?
[take c = 3.0 x 108m/s, 1eV = 1.6
x 10-19J, h= 6.6 x 10-34]
A. 5eV
B. 6eV
C. 10eV
D. 8eV

Answer 1

To find the energy requirement of another energy level, we can use the formula:

E = hc / λ

where E is the energy, h is the Planck's constant, c is the speed of light, and λ is the wavelength.

Given:
λ = 2.1 x 10^-7 m
c = 3.0 x 10^8 m/s

Plugging in the values:

E = (6.6 x 10^-34 J s) * (3.0 x 10^8 m/s) / (2.1 x 10^-7 m)
E = (1.98 x 10^-25 J m) / (2.1 x 10^-7 m)
E = 9.42 x 10^-19 J

To convert this to electron volts (eV), we divide by 1.6 x 10^-19 J/eV:

E = (9.42 x 10^-19 J) / (1.6 x 10^-19 J/eV)
E = 5.89 eV

Therefore, the energy requirement of another energy level from the energy level of -3.7 eV with a wavelength of 2.1 x 10^-7 m is approximately 5.89 eV.

The closest answer choice is A. 5eV.