Hertz produced and detected EM Waves experimentally.
Experimental setup is as shown below.
Inductor coil is a source of very longer voltage. If is connected to the system consisting of two polished metallic spheres s, and s2 connected to metallic plates p and p2 as shown. A detector consists of two polished metallic spheres s3 & s4 connected by metallic ring. Detector is placed with the gap b/w s3 and s4 parallel to the gap s, and s2.
Induction coil produces high voltage which provides energy to the system. Plates p1 and p2 form capacities and with joining them behave inductance. So LC oscillations are setup in the circuit. There oscillation produces EM waves in which electric field vector is along s1 s2 and magnetic field perpendicular to it. When such waves reach the detector 1 to its plane ∴ thus linked with the detector changes EMF is induced due to which sparking is produced b/w s3 and s4. It is the indication of transference of energy to the detector which is due to the flow of EM waves from LC circuit to the detector. On turning the plane of detector by 90 no such sparks are observed which is due to reason dot now magnetic field of the wave becomes parallel to the plane. Hertz was able to prove farther that in EM waves E and B are perpendicular.