when an opaque object is placed closer to the source of light - the shadow formed will be smaller or larger pl calrify

The length of the shadow increases as it gets farther from the light source and gets constant after a point.
Lets understand why shadows are formed in the first place. It is because of an obstruction in the path of light and therefore there is a shadow.
So, if the object is really close: Most of the light gets obstructed and the blocks the light from casting away and hence the shadow is also small.
If the object goes farther: Lesser light gets obstructed and then the shadow formed is also longer.