Question

Exposure to high doses of microwaves can cause cellular damage. Estimate how many photons with λ = 12 cm must be absorbed to raise the temperature of an eye by 5.00 °C. Assume the mass of an eye is 11 g and its specific heat capacity is 4.0 J/g·K.

Answer 1

Answer:

1.33 x 10^26 photons

Explanation:

λ = 12 cm = 0.12 m

Δ T = 5 degree C

m = 11 g = 0.011 kg

c = 4 J/g K = 4000 J / kg K

Let the number of photons are n.

Energy of one photon = h c / λ

Where, h is the Plank's constant and c be the velocity of light.

Energy of n photons, E = n h c / λ

This energy is used to raise the temperature of eye, so

n h c / λ = m c Δ T

n = m c Δ T λ / h c

n = (0.011 x 4000 x 5 x 0.12) / (6.63 x 10^-34 x 3 x 10^8)

n = 1.33 x 10^26

Thus, there are 1.33 x 10^26 photons.