How does the direction of the electric current, moving across a battery powered device, differ from the direction of travel in the ac current sent to homes and businesses?

Starting with only the balmer series light (visible light), how could we ensure that the solar panels generate a current that mark can use for his power station? a)by gradually increasing the brightness (amount) of light that we shine on it. b)by gradually increasing the frequency of the light we shine on it. c)by gradually increasing the wavelength of the light that we shine on it.

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

Which one of the following research methods can show cause and effect