For potassium metal, the work function φ (the minimum energy needed to eject an electron from the metal surface) is 3.68 × 10–19 j. which is the longest wavelength of the following which could excite photoelectrons?
a. 550nm
b.500nm
c.450nm
d.400nm
e.350nm

Although the diagram is not shown, i know that the convection is heated by a the core.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .