Lenses can be used to focus sunlight to a small point to burn paper or dry brush. a person demonstrates this using their own eyeglasses as the lenses. from this you can tell

the eyeglasses consist of a convex lenses

Explanation:

For the lenses to be used to focus light it means the lenses are a convex, because it is convex lenses that converge light towards the focal point for it to burn paper or dry bush. From this we can also deduce that the person is farsighted because convex lenses are used to treat farsightedness.

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.