<span>1.
Measure the mass of an empty container 2. pour the desired liquid in to
this container and wait for it to settle. 3. measure the mass of the
container + liquid 4. subtract the empty container mass to find the
liquid's mass Note: some scales have a tare feature (it defines a weight
of zero), which you measure the container's mass, use the tare option,
and then pour the liquid and wait for it to settle. Also, when you use a
scale, in truth you measure weight. It then divides by the known
gravity field to find a "weight" in kilograms, which we accept to equal
the mass in kilograms. You only truly measure mass when using a balance.
It compares the torque on the balance arm of the object's weight to the
torque on the balance arm of a slide-able weight. A balance will record
the same mass in any gravitational field.</span>
Answer:
Thus, the minimum number of photons per second is 77.34
Explanation:
Light intensity, 
= 
Pupil has a diameter, d = 8.5 mm
= 8.5 x 
m
Radius of the eye, r = 4.25 x m
∴ Area of the eye, A = 
= 
= 
Let 
be the minimum number of photons.
Therefore, = x A
= 
x 
= 
W
Thus the minimum number of photons is given by
where E = 
= 
= 
Therefore, 
= 
= 77.34 photons per second
Thus, the minimum number of photons per second is 77.34
Answer:
On January 22, 2001, EPA adopted a new standard for arsenic in drinking water of 0.01 mg/l or 10 parts per billion (ppb), replacing the old standard of 50 ppb. Water systems had to meet the new standard by January 23, 2006.
Explanation:
