Welcome to Westonci.ca, your one-stop destination for finding answers to all your questions. Join our expert community now! Ask your questions and receive accurate answers from professionals with extensive experience in various fields on our platform. Get detailed and accurate answers to your questions from a dedicated community of experts on our Q&A platform.

The rate at which a quantity M of a certain radioactive substance decays is proportional to the amount of the substance present at a given time. Which of the following is a differential equation that could describe this relationship?
1. dM/dt = -3.72 t^2
2. dM/dt = -0.11M
3. dM/dt = 0.08 t^2
4. dM/dt = 1.2M


Sagot :

Answer:

2. dM/dt = -0.11M

Step-by-step explanation:

Differential equations for proportional amouts:

A differential equation for proportional amounts is given by:

[tex]\frac{dx}{dt} = ax[/tex]

In which a is the constant rate. If the amount increases, a is positive. If it decays, b is positive.

In this question:

Decays, so a < 0.

Proportional to the amount of the substance present at a given time, which means that a multiplies the amount M.

This means that the correct answer is given by option 2.