Answer:Infrared light has a wavelength that is longer than that of standard red light, and although considered part of the red color spectrum, infrared wavelengths are still much shorter
There are no true statements on the list you attached.
Answer:
The tension in the rope is 20 N
Solution:
As per the question:
Mass of the object, M = 2 kg
Density of water, 
Density of the object, 
Acceleration due to gravity, g = 
Now,
From the fig.1:
'N' represents the Bouyant force and T represents tension in the rope.
Suppose, the volume of the block be V:
V =
(1)
Also, we know that Bouyant force is given by:

Using eqn (1):


From the fig.1:
N = Mg + T
40 = 2(10) + T
T = 40 - 20 = 20 N

Force per area is pressure so I think the answer would be air pressure. Relative pressure sounds like it is a measure of pressure relative to something else.