Pixel DensityPixel Density (PPI) is refers to the concentration of pixels on a particular display, measured in pixels per inch (ppi). Pixel density is calculated by dividing the diagonal pixel resolution of a display by its diagonal size, higher pixel density better display quality.
NFCNFC (Near field communication) is a set of standards for smartphones and similar devices to establish peer-to-peer radio communications with each other by touching them together or bringing them into proximity, usually no more than a few inches.