When a comet comes close to the sun, what happens to it that makes it bright and easier to see?

Explanation:

Comet is made by dust particles, icy particles, gases etc.

A comet has a fixed time to complete a revolution around the sun.

As a comet comes nearer to the sun, due to the heat of the sun the vapour and the icy particles becomes gases and due to the radial pressure of energy od sun, we observe a tail of comet which has vapours mainly. SI the comet is visible easily.

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0.11 m/s and 0.28 m/s should be correct