Identify three devices that use convex lenses.

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(and no it doesn't give any options, it can be any device you can think of that uses a convex lense)

Ahydroelectric plant takes energy from water and turns it into electrical energy. what are the transformations of energy in the water molecules that are used in the process of generating electricity this way?

This is the number of complete movements of a wave per second.

The standard cell potential (e°cell) for the reaction below is +0.63 v. the cell potential for this reaction is when the concentration of zn2+ = 1.0 m and the concentration of pb2+ = 2.0 x 10-4 m. pb2+(aq) + zn(s) > zn2+(aq) + pb(s)