Can detect evil see invisible people?

Its mentioned in the Detect Undead spell that this glow allows the caster to see invisible undead. Does this mean all detection spells work like this or is this another effect added on only to the Detect Undead spell?

Side note: How long can Paladins use detect evil for? Is it just the 6 rounds and then they have to meditate again or is it as long as they can set there for?

 
I'm inclined to say that its only the Detect Undead spell only as detect magic only sees the invisibility fog and with no mention of invisible creatures in the detect evil entry but one in the detect magic means to me its intentional. Also detect invisibility is a 2nd level spell making it less useful in general if detect evil can also detect invisible things.  
 

it's probably power creep to allow detect evil to see invisible, but in theory the restrictions on what can be detected might make it fair.  for example, someone simply trying to evade notice of the party but not actively intending to spring an attack might not register on detect evil, and of course that's only for chaotic foes.  Neutral foes intending to do harm can continue to hide invsibly.

If an invisible "evil" creature were within range of the spell, I would have the spell trigger a diffused, smeared glow. The caster would be aware of an evil presence bu unable to locate it.

 

Speaking of hard to locate can it be used to see through stone and other barriers? Through the entire range of the spell? For example can you detect evil through 20 feet of rock or 40 feet of iorn? 

Side note: How long can Paladins use detect evil for? Is it just the 6 rounds and then they have to meditate again or is it as long as they can set there for?

[quote="Demons_eye"] Side note: How long can Paladins use detect evil for? Is it just the 6 rounds and then they have to meditate again or is it as long as they can set there for? [/quote]

The paladin's class description is very explicit that they "can Detect Evil (as the spell)," so it should last as long as the spell normally does: 6 turns, or 360 rounds. There's no limit to the number of times they can use this ability per day, but it takes 1 turn (60 rounds) to activate.

For example: Suppose I'm a paladin strolling along the riverbank, and I spot a mysterious creature on the other side. It's like no beast I've ever seen, so I'm curious as to what its intentions are - and Detect Evil might just give me a hint. I therefore start concentrating.

Ten minutes later, I feel the power of Amonar flowing through me, and I know that I have gained the ability to percieve evil as a mysterious red glow. Alas, the UMA already left while I was concentrating, so I've missed my chance to see if it's evil - but since the ability to see evil auras won't wear off for a full sixty minutes, I've got plenty of time to follow its tracks and catch up.

Later, the mysterious thing turns out to be a gazebo.

Ello?

No, it's blocked by anything that would block light.