Physics

Problem

Two monochromatic lamps each radiate

3.0\,\text{W}

of optical power. Lamp A emits violet light of wavelength

400\,\text{nm}

, while Lamp B emits orange light of wavelength

600\,\text{nm}

. Which of the following statements correctly compares the photon emission rates

R_A

and

R_B

of the two lamps? a)

R_A

is greater than

R_B

because the higher photon energy of violet light requires the lamp to emit more photons to deliver the same power. b)

R_B

is greater than

R_A

because each photon from Lamp B carries less energy. c)

R_B

is less than

R_A

because photons of longer wavelength have lower momentum, so fewer of them are required to convey the same power. d)

R_A

equals

R_B

because the lamps have the same optical power, regardless of wavelength.