Question

Microwave ovens use electromagnetic radiation with a wavelength of about 120 mm to heat food. How many J are there in one photon of this energy?

a) 1.66 x 10ˆ-25 J
b) 1.66 x 10ˆ-21 J
c) 1.66 x 10ˆ-17 J
d) 1.7 x 10ˆ-24 J

Answer 1

Using Planck's equation, the energy of one photon from a microwave oven with a wavelength of about 120 mm is found to be a)1.66 x 10^-25 joules.

Step-by-step explanation:

The student has asked how many joules there are in one photon of energy from a microwave oven with a wavelength of about 120 mm. To answer this question, we need to use the relationship between the energy (E) of a photon and its wavelength (λ), given by Planck's equation E = hc/λ, where h is Planck's constant (6.626 x 10-34 J·s) and c is the speed of light (3 x 108 m/s). Plugging in the given wavelength (0.12 m) and constants, we find the energy of one photon.

E = (6.626 x 10-34 J·s)(3 x 108 m/s) / (0.12 m) = 1.66 x 10-25 J

Therefore, the correct answer is (a) 1.66 x 10-25 J.