question one b
question 2 i think a
3 d
4 c
5 not sure but wanting to say d
6 letter b
7 not sure
8 idk
9 i have no idea
<span>light colored and smooth surface would most likely be the best reflector of electromagnetic energy.Light, shiny surfaces are the best reflectors of radiation and they will allow the waves to reflect and bounce off rather than absorb. we can consider mirror as the example ,it will only reflect the light energy falling on them and it will not absorb. The darker coloured and rough surfaced substances will definitely absorb some amount of light falling on it. so light coloured smooth or shiny surfaced material would be the best reflector for electromagnetic energy.</span>
What’s the question here?
Volume by Displacement. The displacement method (submersion, or dunking method) can be used to accurately measure the volume of the human body and other oddly shaped objects by measuring the volume of fluid displaced when the object is submerged.
The following precautions should be taken very observantly:-
The line of sight must be perpendicular to measuring scale to avoid parallax error. Formation of bubbles inside the cylinder should be completely avoided. Any bubbles within leads to wrong measurements.
Answer:
B. 
Explanation:
Assuming we are dealing with a perfect gas, we should use the perfect gas equation:
With T the temperature, V the volume, P the pressure, R the perfect gas constant and n the number of mol, we are going to use the subscripts i for the initial state when the gas has 20 cubic inches of volume and absolute pressure of 5 psi, and final state when the gas reaches 10 psi, so we have two equations:
(1)
(2)
Assuming the temperature and the number of moles remain constant (number of moles remain constant if we don't have a leak of gas) we should equate equations (1) and (2) because 
, 
and R is an universal constant:
, solving for 
