Two straight rods 55 cm long and 1.4 mm apart in a current balance carry current I, each in opposite directions. If a mass of 1.3 g when placed on the upper rod balances the magnetic force of repulsion between the rods, then calculate the current I.

When you see distant streetlights through smog, they look dimmer and redder than they do normally. but when you see the same streetlights through fog or falling snow, they look dimmer but not redder. use your knowledge of the interstellar medium to discuss the relative sizes of the particles in smog, fog, and snowstorms compared to the wavelength of light.