Yes, it should be.
The site's Help pages do a lot to define the scope of what can and cannot be asked here. New users who take the trouble to go to the on-topic help should expect a reasonably-complete description of the main guidelines.
That said, the Help pages already link directly to the guidelines on meta, and if OP can't be bothered to follow the link then they have a thin case to claim to be surprised by policies they were unaware of. Moreover, the core homework-policy question on meta already includes language explicitly ruling out check-my-work as off-topic:
It's not enough to just show your work and ask where you went wrong. If you just need someone to check your work, you can always seek out a friend, classmate, or teacher. As a rule of thumb, a good conceptual question should be useful even to someone who isn't looking at the problem you happen to be working on. Of course, it's still good to include the text of your problem, just in case (more on that a few paragraphs down).
... but I would argue that this should be clearer. Thus, I would suggest editing point 2 in that list to something like the following:
Ask about the specific concept that gives you trouble
We expect you to narrow down the problem to the particular concept that's giving you trouble and ask about that specifically. That produces a question that is more relevant to others who might be having the same problem, as well as probably more interesting to answer. As a side effect it shows that you're not just being lazy and trying to get us to do your work for you.
The best way to produce a focused, specific question is to show your work and your current understanding. Explain what you've been able to figure out so far and how you did it. Showing your work will help us gauge where you are having problems: if it is a technical thing near the end, a short to the point answer will suffice; if it is some fundamental problem with understanding the subject, somebody will then write a longer, more detailed response. It will also prevent people from spending a lot of time going over ground that you have already covered or understand well already.
It is not enough to just show your work
Questions which only show your attempt at a solution and ask us to check your calculation are also off-topic: it is not enough to just show your work and ask where you went wrong. If you just need someone to check your work, you can always seek out a friend, classmate, or teacher. As a rule of thumb, a good conceptual question should be useful even to someone who isn't looking at the problem you happen to be working on. Of course, it's still good to include the text of your problem, just in case (more on that a few paragraphs down).
Don't just copy the exact problem from your homework assignment or textbook
In particular, when you are asking for help, writing in imperative mode ("Show that...", "Compute...", or "Prove or find a counterexample: ...") is at the very least impolite: you are, after all, trying to ask a question, not give an assignment. It also turns many people off.
Reference the source
And also, for good measure, it should be included in the Help Center as well:
Physics - Stack Exchange is not a homework help site. If you have a question about a homework problem, or any problem of an educational nature, narrow it down to the specific concept that is giving you trouble and ask about that. You can find more information about acceptable homework questions as well as check-my-work questions on our meta site.