I think the logical question here is to either find the distance or the displacement. They differ in such a way that distance is a scalar quantity that does not focus on the direction. Displacement is a vector quantity that covers the distance from the starting point to end point. Because it travels only in one direction (to the east), in this condition, distance is equal to displacement.
Distance = Displacement = 3,000 m + 1,500 m = 4,500 m
Answer: a) 274.34 nm; b) 1.74 eV c) 1.74 V
Explanation: In order to solve this problem we have to consider the energy balance for the photoelectric effect on tungsten:
h*ν = Ek+W ; where h is the Planck constant, ek the kinetic energy of electrons and W the work funcion of the metal catode.
In order to calculate the cutoff wavelength we have to consider that Ek=0
in this case h*ν=W
(h*c)/λ=4.52 eV
λ= (h*c)/4.52 eV
λ= (1240 eV*nm)/(4.52 eV)=274.34 nm
From this h*ν = Ek+W; we can calculate the kinetic energy for a radiation wavelength of 198 nm
then we have
(h*c)/(λ)-W= Ek
Ek=(1240 eV*nm)/(198 nm)-4.52 eV=1.74 eV
Finally, if we want to stop these electrons we have to applied a stop potental equal to 1.74 V . At this potential the photo-current drop to zero. This potential is lower to the catode, so this acts to slow down the ejected electrons from the catode.
Answer:
d. )directed upward.
Explanation:
As the electron has a negative charge, when under the influence of an electric field, is subject to an electric force, which direction is the opposite to the direction of the electric field.
This is because the electric field has the same direction that the force on a positive test charge at the same point.
As the electric field points vertically downward, the electric force on the electron (a negative charge) points vertically upward.
So, the statement d. is the one that results to be true.
Answer:

Explanation:
We can use the equation for the speed

where x is the distance and t the time. In this case we know that the time spent was 2 hours and the distance was 150km. By replacing we have

I hope this useful for you
regards
I think the answer is false