Threshold Frequency Question

[redmosez]

Hey guys so I'm a little confused with threshold frequency, will appreciate some help trying to grasp it.

Let's say that we have a light source but we don't know what type of light it is so we do some tests.

We shine the light into three metals, lets say aluminium, zinc and gold.

Now let's say that the threshold frequency for each is (just making these up)

Aluminium = 800 THz
Gold = 540 THz
Zinc = 400 THz

Now lets say we shine the light into each metal and only Zinc produces a photoelectric effect.

Does this mean that the maximum possible frequency of the light is 539 Hz?

So confused....

[appianway]

Well, if all figures are rounded to the nearest whole numbers, yes. The frequency must also be equal to (or greater than) 400 THz.

[redmosez]

Hmm so can it not still be say 539 THz? because the experiment has verfied that the minimum frequency of the light is 400THz, seeing as it's "worked" with the zinc.

Can we not test the light on a metal with a threshold frequency of say 539THz and it still might work?

or am I missing something?

[redmosez]

Well, if all figures are rounded to the nearest whole numbers, yes. The frequency must also be equal to (or greater than) 400 THz.

Oops didn't read what you said properly

So the maximum possible is 529THz? or is it 549, 999, 999, 999, 999 Hz?