Answer:
f' = 2 f
Explanation:
The frequency of the pendulum that swings in simple harmonic motion is given by :

Where
l is the length of pendulum
g is the acceleration due to gravity
If the length of the thread is increased by a factor of 4, such that, l' = 4 l, let f' is the new frequency such that,



f' = 2 f
So, the new frequency of the pendulum will become 2 time of initial frequency. Hence, the correct option is (b) "2f"
Answer:
I dont know what to answer so im just gonna say ok
After three half-lives have elapsed, the amount of an 8.0 g sample of a radionuclide that remains undecayed is 1.0 g.
<h3>What is Half-Life?</h3>
Half-Life refers to the time it takes for half the amount of a substance to disappear or change.
The nucleus of the atoms of radioactive elements disintegrate to half their starting amounts after every Half-Life.
After three half-lives one-eight of the original atoms remain.
Therefore, after three half-lives have elapsed, the amount of an 8.0 g sample of a radionuclide that remains undecayed is 1.0 g.
Learn more about Half-Life at: brainly.com/question/26689704
#SPJ1