OB. 25 g
OC. 75 g
OD. 100 g
Answer:
B. 25 g
Explanation:
Given:
The initial mass of radioactive isotope is,
There is exponential decay of the isotope with time.
Half life means the time in which the given mass reduces by half. For every half life, the mass reduces by half of the previous mass.
So, for the first half life, the mass that remains is given as:
Now, for the second half life, the mass 50 g is again reduced to half.
So, the mass that remains after 2 half-lives is given as:
Therefore, the radioactive isotope that will remain in the sample after 2 half-lives is 25 g.
Answer:
its 12.5 g for anyone else who had different options
Explanation:
When you lift a box up off the floor, you must exert a force at least equal to the weight of the box. If you lift the box at constant speed, you "do work" on the box that would be equal to the force you exert (the weight of the box) times the height through which you lifted the box. If you exert a force of 50 Newtons on the box and lift it 1 meter high, then you did (50 N)x(1 m) or 50 N-m of work on the object. 1 Newton-meter is called a Joule (J), pronounced "jewel." In lifting the 50 N box upward 1 meter at constant speed, you would do 50 Joules of work on the box. That means your body used 50 J of energy to lift the box.
and here is the Equation for Work: Work = Force x distance, or W = F d.
When you lift a box up off the floor, you must exert a force at least equal to the weight of the box. If you lift the box at constant speed, you "do work" on the box that would be equal to the force you exert (the weight of the box) times the height through which you lifted the box. If you exert a force of 50 Newtons on the box and lift it 1 meter high, then you did (50 N)x(1 m) or 50 N-m of work on the object. 1 Newton-meter is called a Joule (J), pronounced "jewel." In lifting the 50 N box upward 1 meter at constant speed, you would do 50 Joules of work on the box. That means your body used 50 J of energy to lift the box.
and here is the Equation for Work: Work = Force x distance, or W = F d.