megapixel

i learnt that

the higher the pixel the better because

in one square if you have 2 mega pixel = one square will have 2000 pixels

but if its 8 megapixel in the same square, its like 4 times more.

this is because of the density of pixels.

COOL!

Pixels per inch (PPI) or pixel density is a measurement of the resolution of a computer display, related to the size of the display in inches and the total number of pixels in the horizontal and vertical directions. This measurement is often referred to as dots per inch, though that measurement more accurately refers to the resolution of a computer printer. PPI may also be used to describe the resolution of an image scanner or digital camera; in this context, it is synonymous with samples per inch.

For example, a display that is 11 inches wide by 8.5 inches high, capable of a maximum 1024 by 768 pixel resolution, can display about 93 PPI in both the horizontal and vertical directions. This figure is determined by dividing width (or height) of the display area in pixels, by width (or height) of the display area in inches. It is possible for a display's horizontal and vertical PPI measurements to be different. The apparent PPI of a monitor depends upon the screen resolution (that is, number of pixels) and the size of the screen in use; a monitor in 800 by 600 mode has a lower PPI than the same monitor at 1024 by 768 mode. The dot pitch of a computer
display determines the absolute limit of possible pixel density.

The pixel density is useful for calibrating a monitor with a printer; software can
use the PPI measurement to display a document at "actual size" on the screen.

PPI can also describe the resolution in pixels, of an image to be printed within a specified space. For instance, a 100x100-pixel image that is printed in a 1-inch square could be said to have 100 pixels per inch, regardless of the printer's DPI capability. Used in this way, the measurement is only meaningful when printing an image. Good quality photographs usually require 300 pixels per inch when printed.