JAMB Physics 2011 Paper

Concept:The work function of a metal is the minimum energy required to remove an electron from its surface. It is calculated using the threshold frequency of the metal.Explanation:The work function is related to the threshold frequency by the photoelectric equation:$$W = h f_0$$Here, $h = 6.6 \times 10^{-34} \, \text{Js}$ is Planck's constant and $f_0 = 1.3 \times 10^{15} \, \text{Hz}$ is the threshold frequency.Substitute the given values into the formula:$$W = (6.6 \times 10^{-34}) \times (1.3 \times 10^{15})$$Multiply the numerical coefficients:$$6.6 \times 1.3 = 8.58$$Combine the powers of ten by adding the exponents:$$10^{-34} \times 10^{15} = 10^{-19}$$Thus, the work function becomes:$$W = 8.58 \times 10^{-19} \, \text{J}$$Comparing this value with the options given, it corresponds exactly to option A.Answer:$$W = 8.58 \times 10^{-19} \, \text{J}$$The correct option is A.