def lam_to_nu(lam):
    """
    Function to compute frequency (in Hz)
    from Wavelength (in A)
    -----------------------
    Parameters:
    -----------
    lam : float
        wavelength in A
    -----------
    returns
    -----------
    float :
        frequency in Hz
    """
    lam1 = lam*10**(-10)
    freq = 299792458/lam1
    return freq