Answer:
55.7 N
Explanation:
The density of aluminum is 2710 kg/m³. So its volume is:
V = (9 kg) / (2710 kg/m³)
V = 0.00332 m³
The apparent weight is the actual weight minus the buoyant force.
N = mg − B
N = mg − ρVg
N = g (m − ρV)
N = (9.8 m/s²) (9 kg − (1000 kg/m³) (0.0332 m³))
N = 55.7 N
Yes.
In fact, from the graph we see that the threshold frequency (the minimum energy of the incoming energy needed to extract a photoelectron from the material) is 
(we see it because this is the frequency at which the maximum kinetic energy of the emitted electron is zero).
The incoming photon in this problem has a frequency of 8.0 E14 Hz, so above the threshold frequency, therefore it is enough to extract photoelectrons from the material.
When light is incident parallel to the principal axis and then strikes a lens, the light will refract through the focal point on the opposite side of the lens.
To find the answer, we have to know about the rules followed by drawing ray-diagram.
<h3>What are the rules obeyed by light rays?</h3>
- If the incident ray is parallel to the principal axis, the refracted ray will pass through the opposite side's focus.
- The refracted ray becomes parallel to the major axis if the incident ray passes through the focus.
- The refracted ray follows the same path if the incident light passes through the center of the curve.
Thus, we can conclude that, when light is incident parallel to the principal axis and then strikes a lens, the light will refract through the focal point on the opposite side of the lens.
Learn more about refraction by a lens here:
brainly.com/question/13095658
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