Lines A and B shown on the same set of experimental axes represent the variation of…

PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation

Problem

Lines A and B shown on the same set of experimental axes represent the variation of stopping potential V0V_0 with frequency ν\nu for two different metals A and B. Both lines have an identical slope of 4.14×10−15 V s4.14\times10^{-15}\,\text{V\,s} but intercept the potential axis at −1.60 V-1.60\,\text{V} (metal A) and −2.50 V-2.50\,\text{V} (metal B). Use e=1.6×10−19 Ce = 1.6\times10^{-19}\,\text{C} and c=3.0×108 m s−1c = 3.0\times10^{8}\,\text{m\,s}^{-1}. (i) Calculate the work functions of metals A and B in electron-volt. (ii) Find the threshold wavelength for each metal. (iii) A beam of light of wavelength 350 nm350\,\text{nm} is incident on both metals. Predict which metal(s) will emit photo-electrons and justify your answer with numerical calculation.

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