Because the core is a big ball of iron
Average velocity over a given time interval is the distance traveled divided by the time:
Answer:
Position =
behind the mirror
Nature = Virtual and Erect
Size =
: Diminished
Explanation:
Sign convention-Distance measured to the left of pole is negative and to the right of pole is positive.
Object distance = u = -20 cm
Focal length = f = Radius of curvature/2 = 30/2 = 15 cm
We have to use mirror formula to find image distance.

Since the image distance is positive, it is formed behind the mirror or a virtual image is formed.
Magnification = 

Height of the object = 5 cm
Height of the image = 
Since the height of the image is positive and less than the size of object,it is erect and diminished.
The given question is incomplete. The complete question is as follows.
An oxygen molecule is adsorbed onto a small patch of the surface of a catalyst. It's known that the molecule is adsorbed on 1 of 36 possible sites for adsorption. Calculate the entropy of this system.
Explanation:
It is known that Boltzmann formula of entropy is as follows.
s = k ln W
where, k = Boltzmann constant
W = number of energetically equivalent possible microstates or configuration of the system
In the given case, W = 36. Now, we will put the given values into the above formula as follows.
s = k ln W
=
= 
Thus, we can conclude that the entropy of this system is
.