Answer:
D. 21 ml
Explanation:
Since, the cylinder is marked and graduated in the intervals if 1 ml. Therefore, the values between two consecutive ml, such as between 30 ml and 31 ml can not be determined. Because, we do not have any scale in between the ml. So, the least count of this instrument is 1 ml. This graduated cylinder can give the answers to zero decimal places, accurately. And it can not determine any decimal value due to its graduating or the marking limitation. So, all the options given, contain a decimal value, except for the option D. In option D there is no decimal value, hence it is a correct answer.
D. <u>21 ml</u>
Answer:
B. 14
Explanation:
For an element:
- Atomic number: is the number of protons in the nucleus (p)
- Mass number: it is the number of protons (p) + neutrons (n) in the nucleus
For Al (aluminium), we have:
p = 13
p + n = 27
Substituting the first equation into the second one, we find the number of neutrons:
n = 27 - p = 27 - 13 = 14
Benjamin Banneker did this in 1792. Hope this helps
Answer: positive
Explanation: because opposites attract and north=positive and south=negative the answer should be positive.
Yes it is true medium moves parallel to wave motion.