Passage V

Fora photon to free an electron from a metal, the photon's frequency, f, must equal or exceed the threshold frequency, fT, for the metal. If f > fT, the photon has extra energy that is transferred to the electron as kinetic energy, resulting in the ejection of the electron from the metal. Kmax is the highest kinetic energy an ejected electron can have for a given f.

Table 1 displays fT for the metals calcium (Ca), magnesium (Mg), mercury (Hg), and platinum (Pt). Figure 1 is a graph of Kmax versus f for each of the 4 metals. Figure 2 is a graph of a photon's energy versus its f.

24. For a photon to free an electron from Ca, the photon's frequency must be at least:

Answer and Explanation

Your Answer is

Correct Answer is H

Explanation

Look at the first three lines of the first paragraph, the frequency of the photon must be greater than or equal to fT, look at table 1, the fT of Ca is 6.55, so the correct option must be at least equal to 6.55