Physics 9702 · AS & A Level · Photoelectric effect

Photoelectric effect — practice question

(a)[2]

In the photoelectric effect, what does the term work function energy mean?

(b)

The clean metal surface has a work function energy of $5.5 \times 10^{-19}\,\text{J}$. Electromagnetic radiation with wavelength $280\,\text{nm}$ falls on the metal surface. The metal is in a vacuum.

(b(i)1)[2]

Calculate the energy of one photon.

(b(i)2)[3]

Calculate the maximum speed $v_{\text{MAX}}$ of the electrons leaving the surface.

(b(ii))[1]

Explain why most emitted electrons have a speed below $v_{\text{MAX}}$.

(c)[4]

The electromagnetic radiation striking the metal surface can vary either in intensity or in frequency. Complete Fig. 11.1 by adding either 'increases', 'decreases' or 'no change' to show the effects of the changes indicated on the maximum speed and on the rate at which electrons are emitted.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Photon energy needed to eject an electron from the surface

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