Work Function — Prelims Strategy

Prelims Strategy

To excel in NEET questions on work function, a clear strategy is vital. Firstly, thoroughly understand the definition: work function is the *minimum* energy to eject an electron. Memorize the key formulas: $\phi = h\nu_0$ and $\phi = hc/\lambda_0$.

Be proficient in unit conversions, especially between electron volts (eV) and Joules (J), remembering $1,\text{eV} = 1.602 \times 10^{-19},\text{J}$. For numerical problems, always write down given values with units and identify what needs to be found.

Use the simplified constant $hc = 1240,\text{eV nm}$ whenever work function is in eV and wavelength is in nm, as it saves time and reduces calculation errors. For conceptual questions, remember that work function is an intrinsic property of the material and its surface, *independent* of light intensity.

Intensity affects the *number* of photoelectrons, while frequency/wavelength affects the *energy* of photoelectrons and whether emission occurs at all. Practice identifying trap options that confuse intensity with frequency or kinetic energy with work function.

Always double-check calculations, especially powers of 10.