Would cervical cancer show up in an ultra sound?

No, it would show with a pap smear though;

Very unlikely. Best check with your GP if you're worried.
NO, but it will show up on a PAP smear.
No, it would only show up on a pap test.
I really don't know but it may show as a patch of something not instantly recogniseable but so can benign things. But I'm by no means sure.You should get a smear test arranged if you're worried.
No.

You usually have to get a cervical smear test every two-three years which is then sent for analysis and any abnormalities can be checked out.
If it does show on in an ultrasound then it is already a very large tumor. It still cannot tell them if there is a benign tumor or malignant one ...just that something is wrong. Ultrasound cannot distingush activity on a cellular level. That's what the pap-smear does. They actually look at the cells under a microscope with enough magnification to see the DNA (nucleus) This is the only way to definitively catch it at its earliest stages when it is easy to cure.

This is why we do pap-smears at least anually when on birth control since its use can increase the likelyhood of its development. There are other reasons for it to happen like family history as well as HPV infections. There is now a vaccine for teenage girls not yet exposed to HPV virus that helps to prevent it from occuring. It vaccinates you against the most common strains of the virus known to cause cervical cancer. It is well worth the money to get this and in some states now is required to have this vaccine prior to middle school entry.

But the simple answer to your question is ultrasound is not used as a screening method for cervical cancer because it is not large enough to be seen in its early stages. When it is large enough to be seen by ultrasound it has already spread to the lymph nodes and other structures and that is not good news.