I'm deciding on which mobile phone to buy, and since we don't really know if electromagnetic radiation does or does not have adverse health effects (I'm considering cancer and fertility), I'd rather play it safe and take the SAR (https://en.wikipedia.org/wiki/Specific_absorption_rate) into account.

Now I see a lot of phones, that have a low head-SAR and a much higher body-SAR and I wonder why that is, e.g. the Samsung Galaxy A9 (Head SAR : 0.351 W/Kg, Body SAR : 1.587 W/Kg, https://www.samsung.com/sar/sarMain?site_cd=uk&prd_mdl_name=SM-A920F)

AFAIK both measurements are done with the phone emitting on full power, the head SAR with the phone held directly to the head and measurements done directly inside the artificial head. I could not find good information on how the body measurement is done. Is the phone pressed against the waist? How can the value be so much higher? Of course, the body is bigger than the head, but the waves reaching farther away body tissue need to travel a longer distance and thus should lose intensity.


closed as off-topic by John Rennie, Bob D, GiorgioP, Jon Custer, Kyle Kanos Apr 1 at 11:31

  • This question does not appear to be about physics within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 4
    $\begingroup$ I'm voting to close this question as off-topic because it is not a question about physics $\endgroup$ – John Rennie Mar 29 at 10:20
  • $\begingroup$ Since your main concern about cell phones is cancer and fertility, check out the following link search.nih.gov/… $\endgroup$ – Bob D Mar 29 at 13:37
  • $\begingroup$ @JohnRennie Which site would be adecuate for such a question? $\endgroup$ – hunger Apr 12 at 8:02

Should be because the body is thicker, as you say. And also, i am no biologist, but i can imagine that the head and body have different compositions which would also account for this.

Yes, the waves that reach farther into the body have lost intensity on the way, but this intensity isn't "lost" but it is absorbed in the body, thus the total amount basorbed will have gone up.

  • 1
    $\begingroup$ It would be tempting to make a joke about the head-SAR of addictive cellphone users who have nothing but a vacuum in between their ears :) $\endgroup$ – alephzero Mar 29 at 10:29
  • $\begingroup$ Hahaha why would you say that, now i have to exercise self control! @alephzero $\endgroup$ – DakkVader Mar 29 at 10:43
  • 1
    $\begingroup$ That would make sense if the sum (total radiation) would be taken as nominal SAR value, but at least for the head measurement I have read that not the sum of radiation but rather the maximum measured is taken as nominal value. I couldn't find sources for the body measurement but I'd assume that it's the same there. $\endgroup$ – hunger Mar 30 at 10:57

Not the answer you're looking for? Browse other questions tagged or ask your own question.