Hi mates,
Class 11 question,
Pls answer urgently
Suppose you are told that the linear size of everything in the universe has been doubled overnight. Can you test this statement by measuring sides with a measure stick? Can you test this statement by using the fact that the speed of light is a universal constant and has not changed? What will happen if all the clocks in the universe also start running at half the speed?
Answers
I must say, people on Quora ask such intriguing questions!
Since all the measuring instruments would also double in size, it's obvious that we cannot come to know that the size of everything has doubled by measuring the length of things
But there are many other ways by which you can come to know about this 'overnight' change
I am not sure what do you mean by 'linear size', I shall consider that the sizes of objects have doubled in all the 3 dimensions (only then would they retain their shape, or else everything would be distorted)
Now the mass of everything would remain same, only their volume would increase
one-fourth
of what would you used to weigh before, because the radius of the earth has doubled, and your weight is given by GM/r^2
one-eighth
same temperature,
Since the moles of gas in the flask is the same, then at the
From
PV=nRT
Again, I don't think the pressure measuring instrument should be affected
of the previous pressure of the gas, because the volume has become eight times (since radius has doubled and
Also, as you mention in the question, since the speed of light would be the same, light would take twice the time to traverse the length of an object
Furthermore, it is obvious that the length of everything has doubled not due to the doubling of the length of the fundamental particles which make up the object, but due to increase in the void space between atoms
This means the physical properties of everything would be altered drastically, for example, an iron rod would now melt much before its melting point, all metallic objects would become easy to break/stretch and so on...
the same
The universe would now be very much different although it