Was there any choice of answers so i can help or something u have to figure out
An atom's mass number equals the number of protons plus the number of neutrons.
Hope this helps! (:
A concave lens can only form a virtual image. The correct option among all the options that are given in the question is the third option or option "C". Concave lenses are mostly thinner in the middle compared to its edges. I hope that this answer has come to your help.
<h2>Answer: decibels
</h2>
The decibel 
is the relation between two values: the pressure produced by a sound wave and a pressure taken as a reference. Resulting in a dimensionless value.
It should be noted that itself<u> is not a unit of measure</u>, since in reality the unit is bel 
(which <u>is not part of the International System of Units</u>) in honor of Alexander Graham Bell.
However, given the amplitude of the measured elements in practice, its submultiple, the decibel, is used. That is, this quotient is a logarithmic expression, where 
Answer:
Check the explanation
Explanation:
A) 7th Harmonic. (Of an open ended pipe, odd harmonics are allowed (3rd overtone))
b) f = n v / 4 L
n = 7
f = 7 x 350 / 4 x 0.41 = 1493.9 Hz
c) Let level of water H, If reduces the effective length of pipe
Using, f = n v / 4 Leff
n = 1
251.8 = 1 x 350 / 4 ( 0.41 - H)
H = 0.0625m
H = 6.25 cm
