def approx_Q_linear(B: float, T: float):
    """
    Approximate rotational partition function for a linear molecule.

    Parameters
    ----------
    B - float
        Rotational constant in MHz.
    T - float
        Temperature in Kelvin.

    Returns
    -------
    Q - float
        Rotational partition function at temperature T.
    """
    Q = 2.0837e4 * (T / B)
    return Q