Calculate the number of moles in 52g of He

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =