HERTZ 1886 experiments Radio waves Hypothesis Radiation is
- Slides: 6
HERTZ 1886 experiments Radio waves
• Hypothesis: Radiation is emitted at frequencies other than light and UV • AIM: to produce EMR with frequencies other than visible light. • Method: – Create electrical disturbance – i. e Changing electric field • Induction coil – spark across gap. • Have to have accelerating electric charge – Have an antenna / receptor that will produce a spark across a similar gap.
Set up • PROOF
Other experiments: • By using a mirror, Hertz could show these waves are reflected, • Using a prism made from pitch he could show radiowaves are refracted • By reorienting second loop – showed polarisation • All the above are properties of waves.
Velocity of these waves • Using a known frequency of oscillation in the primary spark gap, • Measuring the wavelength using interference patterns, • Calculate speed as 3 x 108 m/s • How?
Then he opened the curtains……. • "I occasionally enclosed the spark B in a dark case so as to more easily make the observations; and in so doing I observed that the maximum spark-length became decidedly smaller in the case than it was before. On removing in succession the various parts of the case, it was seen that the only portion of it which exercised this prejudicial effect was that which screened the spark B from the spark A. The partition on that side exhibited this effect, not only when it was in the immediate neighbourhood of the spark B, but also when it was interposed at greater distances from B between A and B. A phenomenon so remarkable called for closer investigation. "
