Doubtful you would care about theoretical physics in the first place if your IQ was 90.
The best analogy I know of for people in tech, is that you should think of it like having a slightly faster processor with slightly bigger caches. You're more able to manipulate things in your head (thanks to having a bigger stack), react to stimulus faster, change focus easier, and so on.
Someone with a lower IQ is capable of the same tasks, but they are likely to need to expend more effort and time at achieving the same result. From observation I can say the difference is mostly marginal.
As a personal, anecdotal example: One of my parents is in the top 1% of the population, the other is in the top 2% of the population. I have observed many times that my parent in the top 1% will come to a revelation, and voice it -- and as they begin voicing the first syllable or so, the same revelation occurs to the other parent. It's quite amusing. [I feel I should add -- there are cases where the roles are swapped, but that usually only happens when their attentions are focused on separate things].
EDIT: Also note that having a high-IQ doesn't magically make you less-susceptible to bad teaching or incorrect explanations. There exists a sub-society of MENSAns who were told by their tutors that they were slow and stupid, and that they would never amount to anything, and who have low self-esteem and other problems from being told such things.
EDIT 2: An example of someone in science with a low-IQ (of 98), is Julia Robertson, known for her work on Hilbert's tenth question, and her work in decision theory: https://en.wikipedia.org/wiki/Julia_Robinson
Did you get halfway through the first paragraph and reply based on that?
EDIT: Also, the symbol puzzle is timed as well. Most of the IQ questions are perfectly solvable by the average person when given a day to think about it, or 6 hours or so at the least. Raven's Matricies are far easier if you are given 6 hours to dwell on it a little.
Also, with the MENSA test, you aren't just timed on the total test, everyone does the same question at the same time. There's someone reading them out.
Source: My dad was in MENSA and maintained such friendships.
> if it is possible to maintain friendship with high IQ people by a normal IQ people
Yes.
> Do the high IQ people find boring to maintain the thought process and conversation with low IQ people ...
Yes, but not always. High IQ !== does know everything. And usually high IQ people love to learn new things, from anyone who can teach them.
> ... and hence can not enjoy company?
No, it can be enjoyed regardless. Even when you ignore activities not based on conversation (e.g. Sports, games), sometimes you want boring conversation.
That having been said, I apologize for not being able to answer your actual question since I don't know the IQs of the folks I maintain friendships with. Most of them seem like they probably are higher than that range, but that might just be confirmation bias.
Edit: I think people have wildly differing interests, and that IQ and something like theoretical physics go hand in hand.
Issac Asimov wrote an essay years ago about intelligence, where he pointed out that when the doorbell rang, he jumped up and answered the closet. (his IQ was pretty high, and was member of MENSA). Yet, he still marvelled at how smart his mechanic was at fixing his car.
To Asimov, his mechanic was a genius, but his IQ wasn't likely very high, and would therefore correlate neatly with the notion that the mechanic likely could care less about physics. While the reverse was true for Asimov.