He
showed that the nature
of 
their 
vibration,
reflection and refraction
was the same as that of
light and heat waves,
establishing 
their
identity for the first time He 
also 
pioneered
research on discharge of
electricity through gases,
and 
discovered 
the
photoelectric effect HEINRICH RUDOLF HERTZ (1857–1894)
FIGURE 8 3 A linearly polarised electromagnetic wave,
propagating in the z-direction with the oscillating electric field E
along the x-direction and the oscillating magnetic field B along
the y-direction