1 1/2 x 3 1/2
a normal 2X4 weights between 8 to 10 pounds
The standard screw number for securing a 2x4 piece of wood to a wall stud is typically a 8 or 10 screw.
A 2X4 would be a stud, not a board. Weight depends on the length and species, if it is pressure treated or not. 8ft. hem-fir 2X4 is about 8 pounds or so.
no
1 1/2 would be about maximum, making sure it is centered and you use metal protectors on the edges of the stud to keep nails from penetrating.
You will need at least 13-9' 2x4's, on 16" centers, and 2-16' 2x4's for plates. (Deduct plate thickness from stud length)
The color identifies them as "stud grade" pine.
1 and a half inches by 3 and a half inches. Note that an "8 foot 2x4" is 8x12" = 96" long, but a "2x4 stud" is 92 5/8" long to allow for bottom and top plates to make wall framing go quicker.
A 2x4 is still 2x4- UNTIL it is run thru a planning machine. The planer removes about a quarter inch from each face, giving a DRESSED dimension of 1.5 x 3.5. However, undressed (means rough cut, unplaned) lumber is still 2x4.
That dimension will change with the size of the window and the header height.
A 16 gauge metal stud typically weighs around 0.5 pounds per linear foot.
To locate metal studs in a wall, you can use a stud finder that is specifically designed to detect metal. Simply run the stud finder along the wall until it indicates the presence of a metal stud. You can also look for visual clues such as nail heads or electrical outlets, as metal studs are often placed near these fixtures.