Answer:
No
Explanation:
A planetary system consists of at least one star and non stellar objects revolving around it.
Our solar system has one star around which there are 8 planets. However there are star systems with more than one star. These systems are called binary systems. The size of stars also vary. They also vary by orbital configuration i.e, the planets have higher eccentricity than our solar system's. The planetary systems are also classified on the basis of the number of planets in them.
So, all planetary systems do not look the same as our own.
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:
Mass = 4152kg
Explanation:
Given
L = 208m
I = 154A
V = 0.245V
Density = 3610 kg/m3
ρ = 4.23 x 10-8Ω·m = resistivity of wire
Resistance R = ρL/ A
R = voltage / current = V/I = 0.245/154 = 1.59×10-³ohms
1.59×10-³ = 4.23 x 10-⁸×208/A
Rearranging,
A = 4.23 x 10-⁸×208/1.59×10-³
A = 5.53×10-³m²
Mass = density × volume
Volume = L×A = 208×5.53×10-³m³= 1.15m³
Mass = 3610×1.15 = 4152kg
The average velocity can be calculated using the formula:
v = d / t
For the 1st car, the velocity is calculated
as:
v1 = 8.60 m / 1.80 s = 4.78 m / s
While that of the 2nd car is:
v2 = 8.60 m / 1.66 s = 5.18 m / s
Now we can solve for the acceleration using the formula:
v2^2 = v1^2 + 2 a d
Rewriting in terms of a:
a = (v2^2 – v1^2) / 2 d
a = (5.18^2 – 4.78^2) / (2 * 8.6)
a = 0.23 m/s
Therefore the train has a constant acceleration of about
0.23 meters per second.
B is correct.
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