Answer
3.4 X $10^{14}$ Hz
Work Step by Step
The temperature of the surface of the Sun is 5800 K.
The frequency can be found using Wien's Displacement Law:
$f_{peak}$ = 5.88 X $10^{10}$ X T
$f_{peak}$ = 5.88 X $10^{10}$ X 5800 = 3.4 X $10^{14}$ Hz.