Parkinson's disease is a progressive nervous system disorder that can cause tremors in the hands and arms, rigid muscles and speech changes such as slurring, according to the Mayo Clinic. â
Electric power law: P = V x I   P = power in watts   Einstein's law: E â¦ = m x cÂ²   E = energy in joules, m = mass in kilograms, and c is the speed of light.
Confidence votes 103. To calculate the number of photons, you need the formula E=hf where h is Planck's constant with a value of 6.63*10^-34Js and f should be given. If f isn't given, then use the formula C = f * wavelength. Rearrange this formula by using the wavelength given and the C, speed of light, which is 3*10^8. What you also need is the Intensity. This way you obtain the photon flux as: I/E (i.e. the number of photons per unit area and unit time).