Answer:
175s
Explanation:
time it takes sunlight to reach the earth in vacuum
C=light speed=299792458m/s
X=1.5x10^8km=1.5x10^11m
c=X/t
T1=X/c
T1=1.5X10^11/299792458=500.34s
time it takes sunlight to reach the earth in water:
First we calculate the speed of light in water taking into account the refractive index
Cw=299792458m/s/1.349=222233104.5m/s
T2=1.5x10^11/222233104.5m/s=675s
additional time it would take for the light to reach the earth
ΔT=T2-T1=675-500=175s
Answer:Water is easily evaporated, and oil and grease will not evaporate.
Explanation:
The answers are B, C, E and F.
Atoms from an element is mostly made of protons, neutrons, and electrons. Proton numbers are like a class number for each element. Each element has their own and they're all different. And the number of protons are equal to the number of electrons. Therefore, B is correct.
Isotopes. It's different atoms from a same element that has the same number of protons but different number of neutrons. For example in hydrogen, there's 3 Isotopes for hydrogen. Therefore, C is correct.
Again, proton for the same element is never changed, even if they're different Isotopes. So, E is correct.
Isotopes, again, different elements may have different Isotopes. Some has only 1, others may have a few or more. So, F is correct too.