Answer:
B'=1.935 T
Explanation:
Given that
magnetic field ,B= 0.645 T
We know that magnetic filed in the solenoid is given as

I=Current
n=Number of turn per unit length
μ0 =magnetic permeability
Now when the current increased by 3 factors
I'=3 I
Then the magnetic filed


B'=3 B
That is why
B' = 3 x 0.645 T
B'=1.935 T
Therefore the new magnetic filed will be 1.935 T.
It is D,Copernicus.when he first proposed the idea everyone thought he was nuts and that it was not plausible.even though his theory wasn't so accurate it still helped further scientific research.HE was born February 19,1473 and he published a book about his theory.
More energy is being used in the movement
Nothing can travel faster than the speed of light. As such, perceptions of objects and time change as they approach light speed, but the laws of physics remain consistent regardless of speed. Objects will appear shortened and time will appear to slow down around an observer approaching near light speeds, but all quantities still exist as they did before and all causality is preserved, even if observers in different points or traveling at different speeds will report different things.
Answer : The acceleration of the elevator is, 
Explanation :
Formula used to calculate the acceleration of the elevator is:

where,
F = force = 844 M
m = mass of man = 70 kg
g = acceleration due to gravity = 
a = acceleration of the elevator = ?
Now put all the given values in the above formula, we get:



Thus, the acceleration of the elevator is, 