Convert between energy units:

a. 534 kWh to J

b. 215 kJ to Cal

c. 567 Cal to J

d. 2.85 × 103 J to cal

Solution: 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. Step1: a) Given, minimum frequency = 1.09 x 10 s 15 -1 Planck's constant, h = 6.626 x 10 J.s -34 Substituting the values in equation (1), we get, E = (6.626 x 10 J.s) x (1.09 x 10 s ) 15 -1 = 7.22 x 10 J.-19 -19 Thus, minimum energy needed to eject an electron is 7.22 x 10 J. Step2: b) From equation (2), = hc/E Here, Velocity of light, c = 3...