Problem 23 A red laser at 650 nm and a blue... [FREE SOLUTION]

Chapter 34: Problem 23

A red laser at 650 nm and a blue laser at 450 nm emit photons at the same rate. How do their total power outputs compare?

Short Answer

Expert verified

Blue laser provides more overall power output than the red laser, given they emit photons at the same rate.

Step by step solution

Calculate Frequency for Each Laser

Use the formula \(c=f\lambda\) where \(c\) is the speed of light, \(f\) is frequency and \(\lambda\) is wavelength. The speed of light is approximately \(3 \times 10^8 m/s\). The wavelengths for the lasers were given in nm, so these should be converted to meters. For red laser \(\lambda = 650 \times 10^{-9} m\) and for blue laser \(\lambda = 450 \times 10^{-9} m\). After conversion, calculate the frequency \(f\) for each laser.

Calculate Energy Output

Now, use the calculated frequencies to find the energy of one photon for each laser using the energy formula \(E=hf\). Here \(h\) is Planck's constant or approximately \(6.63 \times 10^{-34} Js\). Calculate the energy \(E\) for each laser.

Compare Energy Output

Now it can be observed that blue light has more energy per photon than red light, because blue light's frequency is higher. So, even though they emit photons at the same rate, the overall power output will be greater for the blue laser.

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91影视

A red laser at 650 nm and a blue laser at 450 nm emit photons at the same rate. How do their total power outputs compare?

Short Answer

Step by step solution

Calculate Frequency for Each Laser

Calculate Energy Output

Compare Energy Output

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