Question

Convert the following thermometer readings into Kelvin-10000C, 20000C -10000C.​

Answer 1

Answer:

Which subject which grade

Answer 2

Answer:

If c is the speed of light, λ is the wavelength and f is the frequency, the

equation c = λ · f can be used to calculate one of the the three values, if the

two others are given. The speed of light is defined to be exactly 299792458 m/s

(≈ 3 · 108 m/s). Thus, for a frequency of f = 10 GHz = 10 · 109 Hz,

λ =

c

f

=

299792458 m/s

10 GHz

≈

3 · 108 m/s

1010 Hz = 0.03 = 3 cm

and for a wavelength of λ = 25 cm = 0.25 m

f =

c

λ

=

299792458 m/s

0.25m

≈ 12 · 108 Hz = 1.2 GHz

Problem 2:

The boiling temperature of water at sea level is 100oC. To convert this to

degrees Kelvin, just add 273.15:

100oC = (273.15 + 100)K = 373.15K

Problem 3:

The formula for the wavelength of the energy emission peak is

λmax =

2898 µm K

T

where T is the black-body temperature. Using the temperatures for the surface of

the sun (T = 6000K) and an effective value for the earth (T = 255K), we get

sun: 0.483 µm

earth: 11.4 µm

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