4. What is the half-life of the radioactive isotope with amount A, whose rate of decay in t hours is shown in the graph below? (0,40)
(20,15)

15, 25

Step-by-step explanation:

The half life is the time taken for the amount of a substance to become half of its original value. If we take the initial value to be 30 on the y-axis, the half of 30 is 15. We check the time at which the substance has reduced to 15 atoms and this is about 40 seconds. The answer is C.

Step-by-step explanation:

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.

00

step-by-step explanation: