Answer:
A. The sound wave will reflect off Buildings and automobiles.
Explanation:
This is because the sound waves would more likely propagate through diffraction through buildings and transmission through the air. It is also more likely to be absorbed by buildings than for multiple reflections to occur off buildings and automobiles. In the process of reflection, these materials would absorb the sound energy thereby reducing its ability to reflect.
Intensity:
Decibels
Amplitude:
Meters
Frequency: Hertz
<u>Explanation:</u>
The Wave is not visible to eyes and they can easily propagate through vacuum. the average power travelling at a given period of time in a space is the intensity. Decibels is the measure of intensity. it is measured in the decibel scale. The wave's strength and the intensity gives the amplitude of wave. It is measured using meters.
The wave's amplitude and the energy has a direct proportionality. The number occurrence of wave cycles per second refers to the frequency of wave. it is measured in hertz. it is also measured as the number of cycles that occurs per second.
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.
Explanation: Orange, at 3 meters per second if you calculate the net force being applied to the system.
hope this helps! ✌
Answer:
Q = 2.95*10^5 kJ
Explanation:
In order to calculate the energy required to melt the cooper, you first calculate the energy required to reach the boiling temperature. You use the following formula:
(1)
m: mass of cooper = 540 kg
c: specific heat of cooper = 390 J/kg°C
Tb: boiling temperature of cooper = 1080°C
T1: initial temperature of cooper = 20°C
You replace the values of the parameters in the equation (1):
Next, you calculate the energy required to melt the cooper by using the following formula:
(2)
Lf: melting constant of cooper = 134000J/kg
Finally, the total amount of energy required to melt the cooper from a temperature of 20°C is the sum of Q1 and Q2:
The total energy required is 2.95*10^5 kJ
