Question

An astronomer discovers a star that has a peak frequency of 1.6×10¹⁴ Hz. Determine the temperature of the star's surface.
T =

Determine the peak frequency the average human emits.
peak frequency =

Answer 1

Given,

f = 1.6 x 10^14 Hz

We know that

c = f lambda

lambda = c/f = 3 x 10^8/(1.6 x 10^14) = 1.875 x 10^-6 m

We know that

lambda T = 2.898 x 10^-3

T = 2.898 x 10^-3/(1.875 x 10^-6) = 1545.6 K

T = 1545.6 K = 1272.45 deg C

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We know that Human body has a temperature of 310 K

We know that

lambda T = 2.898 x 10^-3

lambda = 2.898 x 10^-3/310 = 9.35 x 10^-6

f = c/lambda

f = 3 x 10^8/9.35 x 10^-6 = 3.21 x 10^13 Hz

Hence, f = 3.21 x 10^13 Hz