The FREQUENCY of light remains unchanged once it leaves the source.
Answer:
Explanation:
A simple light microscope uses light for imaging of objects where as a transmission electron microscope uses a monochromatic beam of electrons.
This beam is passed by a magnetic field which is very strong and thus act as a lens.
Its resolution of very high which is about 0.2 nanometers because of the separation between two atoms.
Because of this reason its resolution is about 1000 times greater than light microscope.
Answer:
5.71428571422 m/s
Explanation:
u = Initial velocity = 20 m/s
v = Final velocity
s = Displacement
a = Acceleration
Time taken = 15-1 = 14 s
Distance traveled in 1 second = 
The speed as she reaches the light at the instant it turns green is 5.71428571422 m/s
I beleive she isnt doing any work due to holding the box motionless, you must be exerting a force in the direction of the box motion. If she is just standing there holding the box their isn't no work becuase no distance has been covered. work = force = distance.
What are you asking here?
