Question

A) Sparks are produced when a pair of scissors is sharpened against a grinding wheel.

Answer 1

Grinding is the process in which the pieces of metal from the edge of the knife  fall out and due to high temperature on account of friction between two surfaces small pieces will heat up and start to glow, producing sparks.
Hence due to the force of friction , sparks are produced when a pair of scissors is sharpened against a grinding wheel.

Answer 2

Answer:

Sparks are produced because as the wheel has irregularities and it is rough. Thus, due to friction the heat is produced which burns the metal of the knife and causes sparks