There is no <span>radioactive decay</span>
Answer: The correct answer for the blank is -
C. closure.
Gestalt principle of closure describes how we perceive complete figures even when the information that form the figure is missing.
This is due the fact that our brain responds to the familiar patterns inspite of getting incomplete information.
For instance, in the given question, we are able to perceive an image of square in the center despite not having actual lines that form a square.
Thus, it represents principle of closure.
Explanation:
It is given that,
A planet were discovered between the sun and Mercury, with a circular orbit of radius equal to 2/3 of the average orbit radius of Mercury.
Mass of the Sun, 
Radius of Mercury's orbit, 
Radius of discovered planet, 

Let T is the orbital period of such a planet. Using Kepler's third law of planetary motion as :




T = 4135214.625 s
or
T = 47.86 days
So, the orbital period of such a planet is 47.86 days. Hence, this is the required solution.
By the formula of torque balance we know that

here we know that
r = distance of force
F = applied force
so here we know that as we will take large edge knife then the distance of force will increase
due to this the torque will also increase in it so it is easy to pear it
So here we can say


so output force will increase in this case
So here the correct answer would be
<em>b. the longer the knife, the stronger the output force</em>