signs that a plant is not recieving enough light?

i am starting to believe that my seedlings may not be getting enough light? what are the signs that would point to that? any advice or comments would be great

...then put more light? there are really no signs u wanna have like 3000 lumens per sq foot for decent growth so buy some cfls(compact fluorescents)

i have a t-5 i just wasnt sure if i had the plants sitting too far away from the light or not

those have a pretty high heat signature tho dont they?

yea but if u have them high enough from the plants its ok i start my plants for 2 weeks under fluros then throw them under the mh...makes a big difference