  The core component width in normal pulsars, with periods ($P$) $>$ 0.1
seconds, measured at the half-power point at 1 GHz has a lower boundary line
(LBL) which closely follows the $P^{-0.5}$ scaling relation. This result is of
fundamental importance for understanding the emission process and requires
extended studies over a wider frequency range. In this paper we have carried
out a detailed study of the profile component widths of 123 normal pulsars
observed in the Meterwavelength Single-pulse Polarimetric Emission Survey at
333 and 618 MHz. The components in the pulse profile were separated into core
and conal classes. We found that at both frequencies the core as well as the
conal component widths versus period had a LBL which followed the $P^{-0.5}$
relation with a similar lower boundary. The radio emission in normal pulsars
have been observationally shown to arise from a narrow range of heights around
a few hundred kilometers above the stellar surface. In the past the $P^{-0.5}$
relation has been considered as evidence for emission arising from last open
dipolar magnetic field lines. We show that the $P^{-0.5}$ dependence only holds
if the trailing and leading half-power points of the component are associated
with the last open field line. In such a scenario we do not find any physical
motivation which can explain the $P^{-0.5}$ dependence for both core and conal
components as evidence for dipolar geometry in normal pulsars. We believe the
period dependence is a result of an yet unexplained physical phenomenon.
