Explain global climate change. What causes global warming?

Solution: Electromagnetic radiations are the waves having both electric and magnetic fields associated with them. The arrangement of different types of electromagnetic radiations in the order of increasing wavelengths is called electromagnetic spectrum. The complete electromagnetic spectrum is given below: Step1: a) Given, wavelength of the radiation = 3.55 mm = 3.55 x 10 m-3 [1 mm = 10 m]-3 From the above figure, it is seen that the radiation will lie in the microwave region of the electromagnetic spectrum. Step2: b) Again, according to Planck’s quantum theory of radiation, the amount of energy associated with a quantum(in case of light, the quantum of energy is often called photon) of radiation is proportional to the frequency of light, E = h ---(1), where h is a universal constant called Planck’s constant. is the frequency and E is the energy of a photon. Or, E = hc/ -------(2), where, is the wavelength of light and c is the velocity. -3 Given, wavelength of the light = 3.55 x 10 m Planck's constant, h = 6.626 x 10 J.s -34 8 Velocity of light, c = 3 x 10 m/sec Substituting the values in equation (2), we get, -34 8 -3 E = [(6.626 x 10 J.s) x (3 x 10 m/sec)] / (3.55 x 10 m) = 5.6 x 10 J-23 -23 Thus, energy of one photon of the radiation is 5.6 x 10 J. Step3: 8 -23 8 Therefore, energy of 3.2 x 10 photons per sec = (5.6 x 10 J) x (3.2 x 10 ) = 17.92 x 10 -15J = 1.792 x 10 -14J Step4: -14 Thus, total energy of the photons in 1 hour(3600 sec) = 3600 x (1.792 x 10 J) -14 = 6451.2 x 10 J = 6.45 x 10 -11J. -------------