Question

how many pixels are there in one inch ?

Answer 1

Generally, you see this with any device that has a screen to it. Eg: 200 ppi screen, what it means is that there are 200*200 pixels per square inch if the screen. Depends on how many dots per inch (dpi) your display possesses. Indeed, the answer to your question is the dpi of your display.

Answer 2

1 inch = 96 pixels

hope it helps you