Answer:
A. The particle model, because only high-energy frequencies of light can remove electrons .
Explanation:
Each photon of blue light has higher energy than each photon of red light has . So when each photon strikes each electron , it gets ejected . But the photon of red light has not sufficient energy to eject electron . Once the photon of red light strikes the electron , the energy is wasted off . Energy of photon can not be accumulated . Thus photon behaves like particle .
Answer:

Explanation:
As we know that when electron moved in electric field then work done by electric field must be equal to the change in kinetic energy of the electron
So here we have to find the work done by electric field on moving electron
So we have



now the distance moved by the electron is given as

so we have



now we have to convert it into keV units
so we have


Answer:
stress tension tensile strength
Explanation:
The maximum stress which a material can withstand when it is pulled apart is its: stress tension tensile strength.
Answer:
Which sentence from the passage shows that the function of the river depicted here has carried through to modern times?
Explanation:
Which sentence from the passage shows that the function of the river depicted here has carried through to modern times?