Answer:
3
Explanation:
The half-life of a radioactive isotope is the time it takes for the mass of the sample to halve.
This can be rewritten as follows:
where
m(t) is the mass of the sample at time t
m0 is the original mass of the sample
n is the number of half-lives that passed
We see that if we take n=3, the amount of original sample left is
So 3 (3 half-lives) is the correct answer.
Answer:
Yes, it's correct
Explanation:
Newton's second Law states that the acceleration of an object is proportional to the net force applied on it, according to the equation:
where
F is the net force on the object
m is the mass of the object
a is the acceleration of the object
We can re-arrange the previous equation in order to solve explicitely for a, the acceleration, and we find:
So, we see that the acceleration is proportional to the net force and inversely proportional to the mass of the object.
Answer: Option (b) is the correct answer.
Explanation:
Since, there is a negative charge present on the ball and a positive charge present on the rod. So, when the negatively charged metal ball will come in contact with the rod then positive charges from rod get conducted towards the metal ball.
Hence, the rod gets neutralized. But towards the metal ball there is a continuous supply of negative charges. Therefore, after the neutralization of positive charge from the rod there will be flow of negative charges from the metal ball towards the rod.
Thus, we can conclude that negative charge spread evenly on both ends.
