It will take 267 milliseconds for a sample of radon-218 to decay from 99 grams to 0. 50 grams.
We know that half life of a first order reaction is given by: 
where k = rate of reaction
Given half life = 35 milliseconds
So from this we get k = 0.0198
Now we know that rate of first order reaction is given by: 
where t= time
R'= initial amount = 99 g
R= final amount= 0.50 g
k= rate of reaction = 0.0198
Putting values of these in above equation we get t=267 milliseconds.
i.e. It will take 267 milliseconds for a sample of radon-218 to decay from 99 grams to 0. 50 grams.
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Answer:
8.3
Explanation:
thats what i think sorry if its wrong im ok at doing this stuff
Answer:
a) {[1.25 1.5 1.75 2.5 2.75]
[35 30 25 20 15] }
b) {[1.5 2 40]
[1.75 3 35]
[2.25 2 25]
[2.75 4 15]}
Explanation:
Matrix H: {[1.25 1.5 1.75 2 2.25 2.5 2.75]
[1 2 3 1 2 3 4]
[45 40 35 30 25 20 15]}
Its always important to get the dimensions of your matrix right. "Roman Columns" is the mental heuristic I use since a matrix is defined by its rows first and then its column such that a 2 X 5 matrix has 2 rows and 5 columns.
Next, it helps in the beginning to think of a matrix as a grid, labeling your rows with letters (A, B, C, ...) and your columns with numbers (1, 2, 3, ...).
For question a, we just want to take the elements A1, A2, A3, A6 and A7 from matrix H and make that the first row of matrix G. And then we will take the elements B3, B4, B5, B6 and B7 from matrix H as our second row in matrix G.
For question b, we will be taking columns from matrix H and making them rows in our matrix K. The second column of H looks like this:
{[1.5]
[2]
[40]}
Transposing this column will make our first row of K look like this:
{[1.5 2 40]}
Repeating for columns 3, 5 and 7 will give us the final matrix K as seen above.
Answer:
I = 0.0025 kg.m²
Explanation:
Given that
m= 2 kg
Diameter ,d= 0.1 m
Radius ,
R=0.05 m
The moment of inertia of the cylinder about it's axis same as the disc and it is given as
Now by putting the all values
I = 0.0025 kg.m²
Therefore we can say that the moment of inertia of the cylinder will be 0.0025 kg.m².
Answer:
B. 1 m/s
Explanation:
Metric unit conversions:
0.3 km = 300m
5 minutes = 5*60 = 300 seconds
So if a seal can reach a depth of 300m in a time of 300 seconds, its diving speed is the distance divided by time duration
v = s/t = 300/300 = 1m/s
So B is the correct answer
