Suppose he work function for a metal used in the cathode of a photoelectric cell is 2.40x10-19 Joules. Calculate the value of the longest wavelength for light that has just sufficient energy to cause the emission of photoelectrons from the surface of this metal. What is the color of this light?

8.28.25nm

Explanation:

E = 2.40 * 10 ^-19 J

h = 6.626 * 10^-34 J.S

C = 3.0 * 10^8 m/s

Energy - wavelength relationship is

E = hc / λ

λ = hc / E

λ = (6.626 * 10⁻³⁴ * 3.0*10⁸) / 2.40*10⁻¹⁹

λ = 8.28 * 10⁻⁷m

λ = 828.25nm

the wavelength is 828.25nm

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).