Where's a reflecting telescope uses to gather light a refracting telescope uses
a. a lens; a curved mirror
b. a curved mirror; a lens
c. prime focus; focal length
d. focal length; prime focus

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.