Describe two simple experiments to show that currents are induced by currents

Describe a simple experiment to show that the prongs of a sound producing tuning fork are vibrating.

Describe an experiment to show that sound travels through liquids.

(a) Describe a simple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to produce a current which opposes the change of magnetic flux that produces it. (b) The current flowing through an inductor of self inductance L is continuously increasing. Plot a graph showing the variation of (i) Magnetic flux versus the current (ii) Induced emf versus dI/Dt (iii) Magnetic potential energy stored versus the current.

Describe an experiment to show that sound cannot propagate in vacuum.

Describe an experiment to show that the solids expand on heating.

Describe a smiple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to prduce a current which oppose the change of magnetic flux that produce it