  In this paper we study the evolution of core and corona of nine open clusters
using the projected radial density profiles derived from homogeneous CCD
photometric data obtained through the 105-cm Kiso Schmidt telescope. The age
and galactocentric distance of the target clusters varies from 16 Myr to 2000
Myr and 9 kpcto 10.8 kpc respectively. Barring Be 62, which is young open
cluster, other clusters show a uniform reddening across the cluster region. The
reddening in Be 62varies from $E(B-V)_{min}$= 0.70 mag to $E(B-V)_{max}$= 1.00
mag. The corona of six of the clusters in the present sample is found to be
elongated, however on the basis of the present sample it is not possible to
establish any correlation between the age and shape of the core. The elongated
core in the case of young cluster Be 62 may reflect the initial conditions in
the parental molecular cloud. The other results of the present study are (i)
Core radius `$r_c$' and corona size $`r_{cn}$'/cluster radius $`r_{cl}$' are
linearly correlated. (ii) The $r_c/r_{cn}/r_{cl}$ are linearly correlated with
the number of stars in that region. (iii) In the age range 10-1000 Myr, the
core and corona shrink with age. (iv) We find that in the galactocentric
distance range 9 - 10 kpc, the core and corona/cluster extent of the clusters
increase with the galactocentric distance.
