The mass of cesium left afer 120 years if the original mass of cesium is 8640 with an half-life of 30 years, is 540 grams.
<h3>What is half-life?</h3>
This can be defined as the time taken for half the amount of a radioactive substance to decay.
To calculate the amount of cesium left after 120 years, we use the formua below.
Formula:
- R' = R/(
)............. Equation 1
Where:
- R = Original amount of Cesium
- R' = New amount of cesium
- T = Total time
- t = Half-life
From the question,
Given:
- R = 8640
- T = 120 years
- t = 30 years
Substitute these values into equation 1
- R' = 8640/(
) - R' = 8640/

- R' = 8640/16
- R' = 540 grams.
Hence, The mass of cesium left afer 120 years is 540 grams.
Learn more about half-life here: brainly.com/question/25750315
Answer:

Step-by-step explanation:
Given

Required: Express as a perfect square

Add 10 to both sides


Expand

Factorize:

Factorize:


X^2 + X - 12 = 0
(X + 4)(X - 3) = 0
X = -4 and X = 3.
Answer:
9 times
Step-by-step explanation:
Area = length x breadth
area of picture not enlarged = 3 x 5 = 15in²
If length is tripled it becomes , 3 x 3 = 9in
If width is tripled, it becomes , 5 x 3 = 15in
Area of enlarged picture = 9in x 15in = 135in²
amount by which enlarged image is larger = 135in² /15in² = 9