Frequency is a measure of hertz
Answer:
d
Explanation:
neutrons and protons have the mass nearly 1.67*10-24 g
but neutrons have no charge.. protons are positively charged
Answer:
There are often not more than one or two independent variables tested in an experiment.
Answer : The current passing between the electrodes is, 
Explanation :
First we have to calculate the charge of sodium ion.

where,
q = charge of sodium ion
n = number of sodium ion = 
e = charge on electron = 
Now put all the given values in the above formula, we get:

Now we have to calculate the charge of chlorine ion.

where,
q' = charge of chlorine ion
n = number of chlorine ion = 
e = charge on electron = 
Now put all the given values in the above formula, we get:

Now we have to calculate the current passing between the electrodes.



Thus, the current passing between the electrodes is, 
Explanation:
Many meteorites have iron or nickel in them, so they are heavier (and denser) than Earth rocks. Some meteorites have pits (regmaglypts) on the outside, which look like deep thumbprints. Meteorites are not bubbly, and do not have holes. Meteorite are usually not round.