<h3>
Answer:</h3>
15.29 minutes
<h3>
Explanation:</h3>
<u>We are given;</u>
- Original number of counts = 1668 counts
- New number of counts = 1330 counts
- Time is 5 minutes
We are required to determine the half life of the sample;
- We know that half life is the time it takes for a radioactive sample to decay by a half of the original amount.
- To calculate the remaining mass after decay we use the formula;
- N = N₀ × 0.5^n , where N is the remaining amount, N₀ is the original amount and n is the number of half lives.
- Using the formula we can calculate the value of n;
1330 counts = 1668 counts × 0.5^n
Thus,
0.5^n = 0.79736
Introducing logarithm;
n log 0.5 = log 0.79736
Thus,
n = 0.327
But, n = time ÷ half life
Thus,
Half life = time ÷ n
= 5 minutes ÷ 0.327
= 15.29 minutes
Thus, the half life of the unknown sample is <u>15.29 minutes</u>
Answer:
The answer is "26.208 km"
Explanation:
Given value:
Formula:
Answer:
who gives you you this kind of work???
Explanation:
Answer:
400X
Explanation:
Total magnification = power of eyepiece (ocular) × power of the objective lenses
= 10X × 40X = 400X
Assuming constant acceleration or that you want average acceleration, you can use the formula:
acceleration = change in velocity / time
=> acceleration = [ 50 m/s - 15 m/s] / 4 s
acceleration = (35 m/s ) / 4s = 8.75 m/s^2
Answer: 8.75 m/s^2