Correct Answer - Option 4 : 2.0 × 10
-17 J
Concept:
Photon
- A photon is a packet of energy that forms light.
- Each photon has energy E = h ν where ν is the frequency of the wave, h is Planck's constant.
- The energy can also be represented as
\(E = h\frac{c}{λ }\)
where λ is the wavelength, c is the speed of light,
c = 3 × 10 8 m /s
Calculation:
Given,
Wavelength λ = 100 Å
1 Å = 10 -10 m
So, wavelength in meter
λ = 100 Å = 10 2 × 10 -10 = 10 -8 m
The energy can also be represented as
\(E = h\frac{c}{λ }\)
\(\implies E = (6.626 × 10 ^{-34})\frac{3 × 10^8}{10^{-8} } J\)
⇒ E = 19.878 × 10 (-34 + 8 + 8 ) J = 19.878 × 10 - 18 Joule
⇒ E ≈ 2.0 × 10-17 Joule
So, the correct option is 2.0 × 10-17 J