Answer:
The speed of the electron is 1.371 x 10⁶ m/s.
Explanation:
Given;
wavelength of the ultraviolet light beam, λ = 130 nm = 130 x 10⁻⁹ m
the work function of the molybdenum surface, W₀ = 4.2 eV = 6.728 x 10⁻¹⁹ J
The energy of the incident light is given by;
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ J/s
f = c / λ
Photo electric effect equation is given by;
E = W₀ + K.E
Where;
K.E is the kinetic energy of the emitted electron
K.E = E - W₀
K.E = 15.291 x 10⁻¹⁹ J - 6.728 x 10⁻¹⁹ J
K.E = 8.563 x 10⁻¹⁹ J
Kinetic energy of the emitted electron is given by;
K.E = ¹/₂mv²
where;
m is mass of the electron = 9.11 x 10⁻³¹ kg
v is the speed of the electron
Therefore, the speed of the electron is 1.371 x 10⁶ m/s.
Answer:
Explanation:
Given
Wavelength of radiation 
We know Energy of wave with wavelength 
is given by
where h=Planck's constant
c=velocity of light
=wavelength of wave
Hence the energy of the wave with wavelength 784 m is 
Answer:
59.51 mph.
Explanation:
The following data were obtained from the question:
Distance (d) = 147 miles
Time (t) = 2.47 hours.
Speed (S) =?
Speed is defined as the distance travelled per unit time. Mathematically, it is expressed as:
Speed (S) = Distance (d) / time (t)
S = d/t
With the above formula, we can obtain the speed of the girl as illustrated below:
Distance (d) = 147 miles
Time (t) = 2.47 hours.
Speed (S) =?
S = d/t
S = 147 miles / 2.47 hours.
S = 59.51 miles per hour (mph)
Thus, the speed of the girl is 59.51 mph.
Answer:
mechanical and electromagnetic
Explanation:
