Answer:
25% thorium will left after 50 days.
Explanation:
Half life:
A nuclear half is the time period of radioactive material in which its amount remain halved.
In given question it is stated that the half life thorium-234 is 25 days. Which means after passing the 25 days the amount of thorium must be halved of original amount.
For example,
If the original concentration was 100%, than after 25 days it will be 50%.
After 50 days amount of thorium left:
Number of half life = T (elapsed) / T half life
Number of half life = 50/25
Number of half life = 2
At first half life amount of thorium left = 100/2 = 50
After second half life amount of thorium left = 50/2 = 25
Total amount decayed = 50+25 = 75
Amount left after 50 days = 100-75 = 25
25% thorium will left after 50 days.
Answer:
A. a new substance is being produced.
Explanation:
The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.
In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.
The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.
Take for example, let zinc reacts with hydrocholoric acid, HCl;
Zn + 2HCl → ZnCl₂ + H₂
Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.
This is a chemical change and new products have been formed.
B and D are wrong because they are both physical changes.
C is wrong because no information about such is provided by the problem statement.
So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.
A positive acceleration indicates that the object sped up. This means that if you compare the first speed to the second, the second speed should be higher.
A negative acceleration indicates that the object has slowed down. This means that if you compare the first speed to the second, the second speed should be lower.
If an acceleration is 0, it means that it neither slowed down nor sped up.
Now let us analyze your problem by listing down the speed and the time:
At noon: 4 mi/hr
12:30 : 6 mi/hr
2:30 : 2 mi/hr
From noon to 12:30, you will notice that there is an increase in speed. This means that Tommy had a positive acceleration. (Rules out D.)
From 12:30 to 2:30, there is a decrease in speed. This would indicate that Tommy had a negative acceleration. (Rules out C.)
No speed was the same, so acceleration was never 0. (Rules out A.)
From the assumptions above, we can now deduce that the answer is B.
Answer:
What happened?
What was the date, time and duration of the incident or behavior?
How many times did this happen?
Where did it happen?
How did it happen?
Did anyone else see it happen? Who? What did they say? What did they do?
Was there physical contact? Describe it. Demonstrate it.
What did you do in response to the incident or behavior?
What did you say in response to the incident or behavior?
How did the subject of the allegation react to your response?
Did you report this to anyone in management? To whom? When? What they say and/or do?
Did you tell anyone about the incident or behavior? Who? What did they say and/or do?
Do you know whether the subject of the allegation has been involved in any other incidents?
Do you know why the incident or behavior occurred?
Do you know anyone else who can shed light on this incident?
Is there anything else you want to tell me that I haven’t asked you?
Explanation:
Explanation:
Different atoms absorb and emit specific wavelengths of electromagnetic radiation and nothing in between. These absorption and emission spectra are actually used to identify atoms of elements in a substance. This phenomenon is explained by Bohr's theory of quantized energy levels in an atom – called orbital levels. When an electron 'jumps' from a lower to higher orbital level, it absorbs a specific wavelength of electromagnetic radiation specific to the ‘jump’. Vice versa, when an electron 'jumps' to a lower orbital level is emits an equivalent and specific wavelength of electromagnetic radiation.
Learn More:
For more on emission spectra check out;
brainly.com/question/12472637
brainly.com/question/8788867
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