Jack is playing with a Newton's cradle. As he lifts one ball to position A and drops it, it impacts the other balls at position
1 answer:
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Answer:
A. K = 0.546 eV
B. cooper and iron will not emit electrons
Explanation:
A. This is a problem about photoelectric effect. Then you have the following equation:
(1)
K: kinetic energy of the ejected electron
Ф: Work function of the metal = 2.48eV
h: Planck constant = 4.136*10^{-15} eV.s
λ: wavelength of light = 410nm - 750nm
c: speed of light = 3*10^8 m/s
As you can see in the equation (1), higher the wavelength, lower the kinetic energy. Then, the maximum kinetic energy is obtained with the lower wavelength (410nm). Thus, you replace the values of all variables :
B. First you calculate the energy of the photon with wavelengths of 410nm and 750nm
You compare the energies E1 and E2 with the work functions of the metals and you can conclude:
sodium = 2.3eV < E1
cesium = 2.1 eV < E1
cooper = 4.7eV > E1 (this metal will not emit electrons)
iron = 4.5eV > E1 (this metal will not emit electrons)
Answer: The net displacement is 6.40meters
Explanation:
Answer:
Positively charged particle trajectories always follow electric field lines because the electric force on a positively charged particle is in the same direction as the electric field.
Explanation:
For any positive charge the electric field emerges radially outwards and it goes radially inwards for the negative charges.
- From the theory of electric field lines we know that they never intersect each other, either they get merged when the sources are unlike or they repel when the sources are alike. In other words the electric field lines align in the same direction as that of the field.
- So, when a positive charge is released into the an electric field they follow the direction of the field lines because they too have their field lines emerging radially outwards and hence these lines align in the direction of the field.
