For spectral flux considered per unit frequency d ν ν (in hertz), Wien's displacement law describes a peak emission at the optical frequency ν ν peak given by: ν ν peak = x h k T ≈ ≈ ( 5.879 × × 10 10 H z / K ) ⋅ ⋅ T or equivalently h ν ν peak = x k T ≈ ≈ ( 2.431 × × 10 − − 4 e V / K ) ⋅ ⋅ T where x = 2.821 439 372 122 078 893... is a constant resulting from the maximization equation, k is the Boltzmann constant, h is the Planck constant, and T is the absolute temperature. With the emission now considered per unit frequency, this peak now corresponds to a wavelength about 76% longer than the peak considered per unit wavelength. The relevant math is detailed in the next section.