Answer:
Option b. Dark spot
Explanation:
Michelson interferometer gives the path difference of the light as path difference, d as twice the distance moved or covered by the mirror
, x and is given as:
d= 2x
Since, its an even multiple, we obtain a bright fringe
now, when the move half the distance, i.e., 
Therefore, the path difference for half the distance
is:
d = x
As it is clear that its an odd multiple which correspond to dark spot as the final image
65% would be ur answer
hope it helps
Answer:
The answer is gravitational force
Explanation:
The mass of the object does not change by moving it to another place. ... At the center of the earth the net gravitational force is zero, so the weight will be zero, but its masses will remain same. Hence the mass at the centre of earth will be equl to 50 kg.