Considering energy per photon, which listed colour of visible light has the…
2023
Considering energy per photon, which listed colour of visible light has the highest energy?
Answer: A. Blue light — CONCEPTThe energy of one photon is E = hν = hc/λ. Photon energy therefore increases with frequency and decreases with wavelength; changing light intensity…
- A.
Blue light
- B.
Red light
- C.
Yellow light
- D.
More than one of the above
- E.
None of the above
Attempted by 14 students.
Show answer & explanation
Correct answer: A
CONCEPT
The energy of one photon is E = hν = hc/λ. Photon energy therefore increases with frequency and decreases with wavelength; changing light intensity does not change the energy of each photon.
APPLICATION
Compare the named colours by wavelength.
Blue light has a shorter wavelength than yellow and red light, so its frequency is higher.
Using E = hc/λ, the shorter wavelength gives blue light the greatest energy per photon among the listed colours.
CROSS-CHECK
Across these visible colours, wavelength decreases in the order red → yellow → blue. Photon energy follows the reverse order, blue → yellow → red.
Result: Blue light has the highest energy per photon among the listed colours.