Calculation of Number of Photons Emitted by a 60 Watt Bulb in 10 Hours

Step 1: Conversion of Watts to Joules per Second

- The power output of the bulb is given as 60 watts.
- 1 watt is equal to 1 joule per second.
- Therefore, the power output of the bulb is 60 joules per second.

Step 2: Calculation of Energy of Each Photon

- The wavelength of the light emitted by the bulb is given as 6000 angstroms.
- The energy of a photon is given by the equation E = hc/λ, where h is Planck's constant, c is the speed of light, and λ is the wavelength of the light.
- Planck's constant is 6.626 x 10^-34 joule seconds.
- The speed of light is 3 x 10^8 meters per second.
- The wavelength of the light emitted by the bulb can be converted to meters by dividing by 10^10 (1 angstrom = 10^-10 meters).
- Therefore, the energy of each photon is given by E = (6.626 x 10^-34 J s x 3 x 10^8 m/s)/(6000 x 10^-10 m) = 3.31 x 10^-19 joules.

Step 3: Calculation of Number of Photons Emitted

- The number of photons emitted can be calculated by dividing the total energy output of the bulb by the energy of each photon.
- The total energy output of the bulb in 10 hours is equal to (60 joules per second) x (10 hours x 3600 seconds per hour) = 2.16 x 10^6 joules.
- Therefore, the number of photons emitted is equal to (2.16 x 10^6 joules)/(3.31 x 10^-19 joules per photon) = 6.53 x 10^24 photons.

Conclusion: Therefore, a 60 watt bulb emits approximately 6.53 x 10^24 photons of light with a wavelength of 6000 angstroms in 10 hours.