Would presume you are asked to find the volume, since there is no second volume.
By General Gas Law:
P₁V₁/T₁ = P₂V₂/T₂
1.6 * 168 /255 = 1.3*V₂/285
V₂ = 1.6 * 168 * 285 / (1.3*255)
V₂ = 231.095
Final volume ≈ 231 cm³
PE = mgh
Mass, m = 7kg, g ≈ 10 m/s², height = 2m
= 7*10*2
= 140 Joules.
Convex.
Concave curved inward (like how a cave foes in) and convex curves outward. Reflected and refracted do not apply to a lens.
That's the period of time known as one solar "day". We subdivide it into 24 slices which we call "hours". Using this system of time units, the day is about 4 minutes longer than one complete axial rotation of the Earth.
