Hello! I read that p=mv in mid school but now I wonder about light... as per my knowledge photons(particles of light) have zero rest mass if so do they have zero momentum too?? if they have how are they able to penetrate through atmosphere?

Why does lightning travel from clouds to the ground?

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.

What caused magnetic fields? what happens if you keep breaking a magnet in two until you reach a single atom?