Answer:
D. The Federal Reserve Bank can provide a short-term loan to banks
to prevent them from running out of money.
Explanation:
A bank run occurs when a large number of depositors withdraw their deposits simultaneously from a bank.
As the number of withdraws increases, the available cash in the bank decreases until a point that the bank can't give depositors their money.
In these situations, The Federal Reserve Bank acts as a lender of last resort that helps to reinforce the effect of deposit insurance, and to reassure bank customers that they will not lose their money.
Answer:
hi sandra!!
Explanation:
the number 3 is the correct!!
The Aurora is an incredible light show caused by collisions between electrically charged particles released from the sun that enter the earth’s atmosphere and collide with gases such as oxygen and nitrogen. The lights are seen around the magnetic poles of the northern and southern hemispheres.
Auroras that occur in the northern hemisphere are called ‘Aurora Borealis’ or ‘northern lights’ and auroras that occur in the southern hemisphere are called ‘Aurora Australis’ or ‘southern lights’.
Auroral displays can appear in many differents colours, but green is the most common. Colours such as red, yellow, green, blue and violet are also seen occasionally. The auroras can appear in many forms, from small patches of light that appear out of nowhere to streamers, arcs, rippling curtains or shooting rays that light up the sky with an incredible glow.
(a) 
The frequency of an electromagnetic wave is given by:
where
is the speed of the wave in a vacuum (speed of light)
is the wavelength
In this problem, we have laser light with wavelength
. Substituting into the formula, we find its frequency:
(b) 427.6 nm
The wavelength of an electromagnetic wave in a medium is given by:
where
is the original wavelength in a vacuum (approximately equal to that in air)
is the index of refraction of the medium
In this problem, we have
n = 1.48 (index of refraction of glass)
Substituting into the formula,
(c) 
The speed of an electromagnetic wave in a medium is
where c is the speed of light in a vacuum and n is the refractive index of the medium.
Since in this problem n=1.48, we find
Answer:
a) λ = 121.5 nm
, b) 102.6, 97, 91.1 nm
Explanation:
Bohr's model describes the energy of the hydrogen atom
= k² e² / 2m (1 / n²)
A transition occurs when the electron passes from n level to a lower one
- = k² e² / 2m (1 / 
² - 1 / 
²)
Planck's relationship is
E = h f = h c / lam
hc /λ = k² e²/ 2m(1 / ² - 1 / ²)
1 / λ = [k² e² / 2m h c] (1 / ² - 1 / ²)
1 /λ = Ry] (1 / ² - 1 / ²)
a) the first element of the series occurs for = 2
1 / λ = 1.097 10⁷ (1- 1/2²)
1 / λ = 1.097 10⁷ (1- 0.25)
1 / λ = 0.82275 10⁷
λ = 1.215 10⁻⁷ m
λ = 1,215 10⁻⁷ m (10⁹nm / m)
λ = 121.5 nm
b) the next elements of the series occur to
1 /λ λ (10-7m) λ (nm)
3 1 1,097 10⁷ (1-1 / 9) 1,0255 102.6
4 1 1,097 10⁷ (1-1 / 16) 0.9723 97.2
∞ 1 1,097 10⁷ (1 - 0) 0.91158 91.1
