Answer:a) 492 nm; b) 1.78 eV
Explanation: In order to solve this problem we have to use the photoelectric energy balance givenb by:
h*ν=Ek+W where h is the Placnk constant, ν is the frequency of the radiation, Ek is the kinetic energy of the realised electrons and W is the work funcion of the incident metal.
Then we have:
W=h*ν-Ek= h*c/λ-Ek=1240 eV.nm/176 nm=2.52 eV
so the maximun wavelength to realese the electrons is when Ek=0 then
W=h*c/λmax so λmax= h*c/W= 1240/2.52=492.06 nm
Finally if we use 288 nm to realease the electrons, then Ek of the emitted electron from the metal is:
from h*ν=Ek+W we have:
Ek=h*c/λ-W= (1240/288) eV*nm-2.52 eV=1.78 eV
<span> Newtons First Law is applied on my egg experiment because it will not move or change it's acceleration until a force acts upon it. In this case, one example of those forces would be Mr. Baker picking up the egg project. Newton's Second Law is applied because of the acceleration caused by natural forces as the egg is plummeting to the earth.</span>
Answer:
20.4m
Explanation:
72kmhr(1000mkm)(hr3600sec)=20ms
Use principles of conservation of energy.
The initial kinetic energy of the car is equal to the work done by friction during braking:
KE=Wfric
12mv2=(Ffric)d
but the force of friction = weight of the car = mg
12mv2=mgd
mass cancels in both terms, which tells us the answer is independent of mass
12v2=gd
12202=(9.81)d
d=20.4m
Note that the correct answer should actually be 20. m with only 2 significant figure accuracy since 72 km/hr only has 2 sig fig accuracy.
You are going 600 miles per hour.