Answer: A, a polished pale yellow surface would likely be the best reflector of heat energy.
Answer:
Option B. 6.25 J/S
Explanation:
Data obtained from the question include:
t (time) = 2secs
F (force) = 50N
d (distance) = 0.25m
P (power) =?
The power can be obtained by using the formula P = workdone/time.
P = workdone / time
P = (50 x 0.25)/ 2
P = 6.25J/s
Answer:
Intensity
Explanation:
The intensity of a sound wave is equal to the ratio between to the power emitted by the source divided by the area of the spherical surface through which the wave propagates:

where
P is the power
is the area of the spherical surface
r is the distance from the source
As we see from the formula, the intensity is inversely proportional to the square of the distance from the source:

so, intensity is the correct answer.
Divide 10 by .05 and that is your answer
Answer:
It takes 10.5 minutes to kill all the bacteria.
Only 1 cell would remain after 9 minutes.
Explanation:
It will take 1.5 minutes to kill 90% of the cells. So, after 1.5 minutes, only 10% would remain. After 3 minutes, only 1% remain. So, to figure out how long it would take to kill a million cells, we have to multiply 1 million by 0.1 repeatedly until the final value is less than 1 that is because when the value is less than 1, it means there are no more bacteria.
So:
= 0.1
So, you need 10.5 minutes of killing to kill one million cells.
Time taken= 7 x 1.5 minutes = 10.5 minutes.
After 9 minutes you would have:
= 1 cell left