Question

The work function of a metal is 4.2 eV, its threshold wavelength will be

• A. $4000\stackrel{\circ }{A}$
• B. $3500\stackrel{\circ }{A}$
• C. $2955\stackrel{\circ }{A}$
• D. $2500\stackrel{\circ }{A}$

Answer 1

The correct option is C

$2955\stackrel{\circ }{A}$

$W_0\left(eV\right)=\frac{12375}{{\lambda }_0}\Rightarrow {\lambda }_0=\frac{12375}{4.2}\approx 2955\stackrel{\circ }{A}$