• # question_answer Work function of a metal is 2.1 eV. Which of the waves of the following wavelengths will be able to emit photoelectrons from its surface  A) 4000 $\overset{\text{o}}{\mathop{\text{A}}}\,$, 7500 $\overset{\text{o}}{\mathop{\text{A}}}\,$ B) 5500 $\overset{\text{o}}{\mathop{\text{A}}}\,$, 6000 $\overset{\text{o}}{\mathop{\text{A}}}\,$ C) 4000 $\overset{\text{o}}{\mathop{\text{A}}}\,$, 6000 $\overset{\text{o}}{\mathop{\text{A}}}\,$ D) None of these

[d] Threshold wavelength ${{\lambda }_{0}}=\frac{12375}{2.1}=5892.8\,\overset{\text{o}}{\mathop{\text{A}}}\,$