Answer:
n = 3
Explanation:
Given the formula for the transition energy of an atom with 1 electron:

For the H transition n=5 to n=2:

Then we solve for nf with Z=2 (Helium)


Is near 3, actually the energy of the transitions are:
H (5⇒2) = -2.85 eV = 434 nm (Dark blue)
He (4⇒3) = -2.64 eV = 469 nm (Light blue)
I thought it was cool to see the actual colors. Included them.
Answer: kindly check explanation
Explanation:
Given the following :
Measured density of copper block:
8.6+/-0.2 g/cm3
True density = 8.96g/cm3
Standard deviation = 0.4g/cm
a. What is the high and low number of the confidence interval range?
High : 8.6 + 0.2 g/cm3 = 8.8g/cm³
Low : 8.6 - 0.2 g/cm3 = 8.4g/cm³
Does the true value fall within the confidence interval? NO
Actual density = 8.96g/cm³ doses not lie in between (8.4 - 8.8)g/cm³
B.) High and low of the standard deviation range?
High = 8.6 + 0.4 = 9.0g/cm³
Low = 8.6 - 0.4 = 8.2g/cm³
Value falls within range of the true density value of copper block.
8.96g/cm³ falls in-between (8.2-9.0)g/cm³
Answer: Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely.
Explanation:
Matter is the basic unit of all things in the world, whether living or nonliving. It is not only useful in chemistry, but also to other fields of science like physics. Physics deals with motion, so it has something to do with matte especially the movement of molecules for solids and fluids.
Answer : Hydrogen fuel cells are considered to be better than fossil fuels because of many reasons, some of them are mentioned below;
a) It is a clean fuel it does not causes any pollution to the atmosphere.
b) It more efficient than many other available fuel cells.
c) Preparation of hydrogen fuel cell relies on the free or compounded state availability hydrogen in nature, which in plenty.
d) They do not make any noise while it is being used. Hence these are considered to be quiet fuel cell.
e) They can be used for longer hours as compared to other fuel cells.