How many elements have been found so far?<br> A. 63<br> B. 90<br> C. 103<br> D. 118

Determine the a) energy (in eV) and b) wavelength (in cm) corresponding to blue light of frequency 670 THz

Lesechka [4]

Answer :

(a) The energy of blue light (in eV) is 2.77 eV

(b) The wavelength of blue light is $4\times 10^{-5}cm$

Explanation:

The relation between the energy and frequency is:

$Energy=h\times Frequency$

where,

h = Plank's constant = $6.626\times 10^{-34}J.s$

Given :

Frequency = $670THz=670\times 10^{12}s^{-1}$

Conversion used :

$1THz=10^{12}Hz\\1Hz=1s^{-1}\\1THz=10^{12}s^{-1}$

So,

$Energy=(6.626\times 10^{-34}J.s)\times (670\times 10^{12}s^{-1})$

$Energy=4.44\times 10^{-19}J$

Also,

$1J=6.24\times 10^{18}eV$

So,

$Energy=(4.44\times 10^{-19})\times (6.24\times 10^{18}eV)$

$Energy=2.77eV$

The energy of blue light (in eV) is 2.77 eV

The relation between frequency and wavelength is shown below as:

$Frequency=\frac{c}{Wavelength}$

Where,

c = the speed of light = $3\times 10^8m/s$

Frequency = $670\times 10^{12}s^{-1}$

So, Wavelength is:

$670\times 10^{12}s^{-1}=\frac{3\times 10^8m/s}{Wavelength}$

$Wavelength=\frac{3\times 10^8m/s}{670\times 10^{12}s^{-1}}=4\times 10^{-7}m=4\times 10^{-5}cm$

Conversion used : $1m=100cm$

The wavelength of blue light is $4\times 10^{-5}cm$

7 0

3 years ago

Which of the following is true when 1 M KCl is diluted to semi-molar KCl?

eimsori [14]

The solution before dilution and after dilution contains same number of moles, and water is added for dilution.

Option B

<h3><u>Explanation:</u></h3>

Suppose before dilution, the solution contains x moles of KCl in Y liter of water. Now as the concentration got halved, then the solution contains x moles of KCl in 2Y kiters of solution. So the number of moles of KCl in the solution remained constant.

Again, as the solution is diluted to half of the concentration, water must have been added with the solution to make it dilute.

4 0

3 years ago

Identify the reactants and products in the following chemical equation: Zn +2HCl --> ZnCl2 + H2 *

Ad libitum [116K]

Answer:

A.

Explanation:

zinc and hydrochloric acid reacts to form zinc chloride and hydrogen.

hope it helps. :)

7 0

2 years ago

Which of these elements has the smallest atomic radius?

shutvik [7]

Answer:

Its Br on Ap ex

Explanation:

Just got it wrong ;( it's B

4 0

3 years ago

Forrest spills some acid on the lab floor. He notifies his teacher and begins to look for baking soda to neutralize the acid on

riadik2000 [5.3K]

The other students in the lab should be notified next in this type of scenario.

This is a substance which donates protons and is very corrosive. It also turns blue litmus paper red.

When it was spilled and baking soda was used to neutralize it on the floor , it is best to inform the other students too so as to prevent them from being exposed by mistake thereby reducing risk of injury.

Read more about Acid here brainly.com/question/25148363

#SPJ1

5 0

1 year ago

How many elements have been found so far? A. 63 B. 90 C. 103 D. 118