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AS photoelectric cell question

Why is the work function negative here? Like it doesn’t make sense to have negative energy, no?

21ED021D-C8A0-4CDD-ADEA-2CF6B4AADD93.jpg.jpeg

Reply 1

nzy

The work function is still positive, but the value of the y-intercept is equal to negative work function. Think about what the graph is showing, and remember that the y-axis represents the maximum kinetic energy of the photoelectrons - in order for an electron to be emitted, with 0 or more kinetic energy afterwards, energy needs to be transferred to it. So when an electron is still bound in the surface of the metal, you can say it has 'negative kinetic energy' (although, as you've correctly mentioned, that's not quite the case - but it works as a graphical model of the kinetic energy here).

Reply 2

Kallisto

Entertainment Forum Helper

Original post by at.midnight

Why is the work function negative here? Like it doesn’t make sense to have negative energy, no?

21ED021D-C8A0-4CDD-ADEA-2CF6B4AADD93.jpg.jpeg

Referring to the y-intercept below, it is shown which energy value of work function is required at least to remove an electron from a surface of a metal. From the marked position of the work function up to the x-intercept (threshold frequency) that is the difference to overcome the threshold for removing, and this difference is generally indicated as a negative sign.