Question

plzzz answer these all​

Answer 1

Answer:

20. Tyndall effect:

It is also called as Tyndall phenomenon.

Scattering of a beam of light by a medium containing small suspended particles.

17. Principle of electric motor:

an electric motor utilises the magnetic effect of current. It works on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it a force acts on the coil which rotates it continuously