When a psychologist simply records the relationship between two variables without manipulating them, it is called a correlational study.
The observed relationship does not by itself reveal which variable causes the other. This is the directionally problem. Also, the relationship may be due to a third variable controlling both of the observed variables.
Answer: Eye injury
Explanation: small material such as dust, dirt, and metal shards can harm your eyes with potential blindness or infection.
1.Only suitable for dc
2.more expensive than moving iron type
3. Easily damaged
Answer:
Explanation:
Approximately, we can use the ideal gas law, below we see how we can deduce the density from general gas equation. To do this, remember that the number of moles n is equal to 
, where m is the mass and M the molar mass of the gas, and the density is 
.
For air 
and 
So, 
