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makvit [3.9K]
3 years ago
7

Help please number 8 an 9

Physics
1 answer:
Murrr4er [49]3 years ago
5 0
8) The reason is that MRIs use radio-waves, which are electromagnetic waves with lower frequency, and so lower energy, than X-rays.
In fact, typical frequencies for radio waves are f=10-10^9 Hz, while X-rays have typical frequencies of 10^{16} - 10^{19} Hz. Since the energy of a wave is given by
E=hf
where h is the Planck constant and f the frequency, we see that the lower the frequency, the lower the energy. Therefore, radiowaves have less energy than X-rays, so they are less ionising and less dangerous than X-rays.

9) The false statement is:
a) gamma-rays are low-frequency waves.
It's actually the opposite, in fact: gamma rays are the electromagnetic waves with higher frequencies (above 10^{20}Hz).

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