Higher strength. If you are framing over 12' you will need to double the 2 x 4s or go to a 2 x 6 stud. Sometimes 2 x 6s are used to make the cavity larger to allow pipes to be concealed within the wall. Sometimes they are used to bump the insulation value from a R13 to a R19.
Wood 2x4 or 2x6's
You can get more insulation when using 2x6 studs rather than 2x4 studs
2x4, 2x6 and 2x10
Answer By putting your ear to the wall : A wall is a collection of studs (usually sized 2x4 or 2x6) equally spaced (usually 16 in. or 24 in. on center) and sandwiched between top and bottom plates. : If you start from the corner, you can measure 16" or 24" and hope that you find a stud. You can hit the wall, and where it sounds more hallow, no stud exists where the sound is higher, there is a stud. But if you can't tell a difference, then measuring could be your only bet.
If the breaker does not trip or a circuit stops working, you don't. Proper installation of house wiring puts the conductors in the middle of the stud. 1.5" in a 2X4 wall and 2.75" in a 2X6 wall. Picture hanging nails should not protrude that far into the wall.
It varies with the thickness of the insulation Generally, about R-3 per inch. 3 1/2" for a 2x4 stud cavity is R-11. 5 1/2" for a 2x6 stud cavity is R-19. But if there is any airflow it greatly reduces the insulating value. Also, the thermal bridging of wood structures reduces the performance of fiberglass insulation.
2x1 is 2 2x2 is 4 2x3 is 6 2x4 is 8 2x5 is 10 2x6 is 12
A 2X6 is 5 1/2 inches wide. Incidentally it's 1 1/2 inches thick. Pre-WWII lumber was cut at stated dimensions, a 2x4 was actually 2 inches by 4 inches.
Lumber yards and home improvement stores in the U.S. generally stock stud length 2x6's (92-5/8").
Well, it could be any 2+ sided shapes. A square (4x5), a rectangle (2x6 then 2x4 perhaps?), or any other shape.
12
Yes, a W-8X18 will carry the weight of a basement load wall 2X6 over a 200 feet span.