5. You have blindfolded your friend and then gave him a lens for recognition. He moves his fingers on the lens and declaresit convex lens. State the reason​

i need the answer to this too but idk it ; -;

positive reinforcement? ?

the amount of current in the coil

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.