In a photoemissive cell with executing wavelength \[\lambda \], the fastest electron has speed v. If the exciting wavelength is changed to \[3\lambda /4\], the speed of the fastest emitted electron will be [CBSE PMT 1998]

• A.            \[v\ {{(3/4)}^{1/2}}\]        
• B.            \[v\ {{(4/3)}^{1/2}}\]
• C.            Less than \[v\ {{(4/3)}^{1/2}}\]                                        
• D.            Greater than \[v\ {{(4/3)}^{1/2}}\]