Chemistry, 31.01.2020 03:56, lordcaos066

Ametal foil has a threshold frequency of 5.45× 1014 hz. which of the colors of visible light have enough energy to eject electrons from this metal?

a. red
b. orange
c. yellow
d. green
e. blue
f. indigo
g. violet

Answers: 2

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answered: Jabari8728

The colors of visible light that have enough energy to eject electrons from this metal?

g. Violet

f. Indigo

e. Blue (Cyan)

d. Green

Explanation:

1) Visible light frequency spectrum:

You need to look for the spectrum of frequencis of the visible light in a textbook or internet.

This is such spectrum:

Violet 680–790 THz

indigo 620–680 THz

Cyan 600–620 THz

Green 530–600 THz

Yellow 510–530 THz

Orange 480–510 THz

Red 405–480 THz

2) Photoelectric effect

The photoelectric effect is the emission of electrons from a metal surface when a ray of light of enough energy shines on the surface of the metal.

The energy of ligth is directly related to the frequency, as the Planck - Einsen's equation shows:

E = hν

Where

E = energy of a photon of lighth = Planck's constantν = frequency of the light

3) If the frequency of the ligth is below the threshold frequency of the metal, the electrons will not be emited.

Taking into account that 1 T unit = 10¹² units, 5.45 × 10¹⁴ Hz = 545 × 10¹² Hz = 545 THz, the coiors with frequency below 545 THz will not eject electrons from this metal.

These are the color which does have enough energy to eject electrons from this metal:

g. Violet 680–790 THz

f. Indigo 620–680 THz

e. Blue (Cyan) 600–620 THz

d. Green 530–600 THz

answered: Guest

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.

answered: Guest

the dissociation of nickel hydroxide is follows:

$ni(oh)_2 > ni^2^+ + 2 oh^-$

$ksp for no(oh)2 = 5.5 * 10^-^1^6$

$5.5 * 10^-^1^6 = s * (2 s)^2 = 4 s^3$

$s^3 = 137.5 * 10^-^1^8$

$s = 5.14 * 10^-^6 = [oh^-]$

the concentration of hydroxide ion is

$5.14 * 10^-^6 = [oh^-]$

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

$k = [ ni^2^+] * [oh^-]^2$

$6.1 * 10^-^1^6 = [ ni^2] * [5.14 * 10^-^6]^2$

$[ ni^2^+] = 0.23 * 10^-^4 mol /l$

thus, concentration of ni is 0.23 * 10^-^4 mol /l

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Ametal foil has a threshold frequency of 5.45× 1014 hz. which of the colors of visible light have en...