The half-life of the radioactive element krypton-91 is 10 seconds. if 16 grams of krypton-91 are initially present, how many grams are present after 35 seconds? a=a0ekt

1.415 gram of the element will be left.

Step-by-step explanation:

The decay of radioactive element Krypton-91 can be formulated as  

............ (1)

where, is the initial amount of the element.

is the amount of element left after t seconds.

And k is a rate constant.

Now, given that the half-life of the element is 10 seconds.

So, from equation (1) we get

taking ln on both sides, we get.

ln 0.5 = -10k

⇒ k = 0.0693

So, the equation (1) becomes ........ (2)

Now, if 16 gram of the element are initially present, then we asked to determine the amount of the element left after 35 seconds.

So, from equation (2) we have gm.

So, 1.415 gram of the element will be left. (Answer)

i think ur answer is   (3,-1)

answer

a,b, and d

explanation

a reflection angle is more than

but less than;

an angle that measures

is a reflex angle.(true)

an angle that measures less than

is acute.(true)

provided we are considering angles greater or equal to zero.

an acute angle lies in the range.

an obtuse angle is less than 180° but more than 90°

an angle that measures 300° is obtuse (false)

an angle that measures 65° is an acute angle.(true)