The half-life of an isotope is the time for its mass to decay by 2. For example, polonium-210 has a half-life of 40. So, a sample of 100 g would decay to 50 g in 40 weeks. The percent, P, of polonium remaining after t weeks is given by the formula P = 100 * (0.5) ^ (1/40) . What percent, to the hundredth of a percent, of polonium remains after 30 weeks?

the diameter is 16 cm. are you a teacher?

step-by-step explanation:

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.