On the incomplete ray diagram for an object in front of a curved mirror, trace the path of Ray 1 as you would do to find the location and size of the image. F labels the focal point of the mirror.
You do not have to trace additional rays for this question.

Explanation:

The curved mirror shown is a converging lens.

To find the location and size of the image formed by a converging lens, you must draw two rays: one ray is from the upper tip of the object (the pen in your figure) that is in front of the mirror, parallel to the horizontal axis until the lens (Ray 1 in your figure) which then bends through the focal point (F in your figure). That is the ray that you must complete in your figure.

The attached figure shows this ray in blue.

The other ray would be from the upper tip of the pen straight through the center of the lens (this is not included in the figure, by instructions of the question).

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach