Question

Please explain I really need help

Answer 1

Answer:

1. 1343 years

2. 9 hours

3. 39 years

Step-by-step explanation:

1. Given, half-life of carbon = 5730 years.

∴ λ = 0.693/half-life of carbon = 0.693/5730 = 0.000121

If N₀ = 100 then N = 85

Formula:- N = N₀*e^(-λt)

∴ 85 = 100 * e^(-0.000121t)

∴㏑(-0.85)=-0.000121t

∴ t = 1343 years

2. Given half-life of aspirin = 12 hours

λ = 0.693/12 = 0.5775

Also N₀ = 100 then 70 will disintegrate and N = 30 will remain disintegrated.

∴ 70 = 100 *e^(-0.05775t)

0.70 = e^(-0.05775t)

㏑(0.70) = -0.05775t

∴ t = 9 hours

3.  The population of the birds as as A=A₀*e^(kt)

Given that the population of birds fell from 1400 from 1000, We are asked how much time it will take for the population to drop below 100, let that be x years.

The population is 1400 when f = 0, And it is 1000 when f = 5

We can write the following equation :

1400 = 1000e^(5t).

∴1400/1000 = e^(5k)

∴ k = ㏑(1.4)/5

We need to find x such that 1400/100 = e^(xk)

14 = e^(xk)

∴ x = 39 years