QUESTION ONE

a) The temperature of the visible surface of the sun, the photosphere, is around 5570 C. (The temperature of the inside of the sun is much hotter.). At what frequency does the Sun emit its peak radiation?

B) What is the wavelength of this radiation?

_peak = ______ n

c) The human eye has evolved so it can detect electro-magnetic radiation with wavelengths of from roughly 380m to 720m. This is the visible light spectrum. This would appear to make sense based on the location of the peak of the radiation spectrum from the sun. The tungstan filement of standard incandescent household light bulb operates at a temperature of around 2620 C. At what frequency does the bulb emit its peak radiation?

f_peak =______ /sec

d) What is the wavelength of this radiation?

_peak = ______nm

e) This isn't very good, right? The peak is well outside the visible spectrum so a lot of the radiation produced by the bulb is wasted. (Unless of course, you're using the light bulb to heat up something.) We can fix this by making the bulb more like the sun. By surrounding the filament of the bulb with halogen gas (or gasses from the same chemical group like iodine or bromine), we can allow the filament to operate at a higher temperature. The filament in halogen light bulb operates at a temperature of around 3090 C. At what frequency does this bulb emit its peak radiation?

f_peak = ______ /sec

f) What is the wavelength of this radiation?

_peak = ______

QUESTION TWO

An electron and a proton each have a thermal kinetic energy of 3k_BT/2. Calculate the de Broglie wavelength of each particle at a temperature of 2030 K. (k_b is Boltzmann's constant, 1.38x10^-23 J/K).

a)Wavelength of the electron =___0.00000000244___m (CORRECT!)

b)Wavelength of the proton =______ m