A magnet is surrounded by , which applies a push or a pull to an object without actually touching it.

A magnetic field

Explanation:

The force is exerted Over a distance and includes forces of attraction and repulsion.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.