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Q1. The energy levels of a certain atom have the following pattern:
E_{1}= -340eV (n = 1),
E_{2} = -85 eV (n = 2),
E3 = -37.78eV (n = 3), and so on..
An electron drops from n=3 to n=1 in this atom. What is the wavelength in nanometers of the photon emitted in the process? Planck's constant h = 6.626 x 10^{-34} Joule-sec, 1eV = 1.6 x 10^{-19} Joules.
Q2. How Many photons per second come out of a ruby laser that is giving out 2 milliwatts of power? (1 watt = 1 Joule/sec and 1 eV = 1.6 x 10^{-19} Joules). Look up the for what wavelength a ruby laser produces.
Q3. You have three liquids: ethyl alcohol, chloroform and ice-cold Water. When you mix 100 grams of ethyl alcohol at a temperature of T=25 Celsius with 200 grams of ice-cold water (T= 0C), the resulting mixture has a temperature of 5.55 C. When you mix 200 grams of ethyl alcohol at a temperature of T=25 Celsius with 100 grams of chloroform at T=10 C, the resulting mixture has a temperature of 22.22 C. What is the final temperature when you mix 150 grams of ethyl alcohol at T=15 C with 250 grams of chloroform at T=5 C? (You are given that the specific heat capacity at water is 4.2 J/g.K).