In a Xerox machine, the black ink's toner particles are negatively charged. They strongly stick to the white A4 sheet paper and form letters and images. What charge should the A4 sheet possess for this process to take place?
Both (a) and (c)
For the negative charge to stick to the paper, the paper should be either neutral or electron deficient. The charge difference creates the force of attraction between them and hence, we see it as a black ink painted on the paper.