What information about elements can be collected from the periodic table?
2 answers:
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The acorn was at a height of <u>4.15 m</u> from the ground before it drops.
The acorn takes a time t to fall through a distance h₁, which is the length of the scale. When the acorn reaches the top of the scale, its velocity is u.
Calculate the speed of the acorn at the top of the scale, using the equation of motion,
Since the acorn falls freely under gravity, its acceleration is equal to the acceleration due to gravity g.
Substitute 2.27 m for s (=h₁), 0.301 s for t and 9.8 m/s² for a (=g).
If the acorn starts from rest and reaches a speed of 6.067 m/s at the top of the scale, it would have fallen a distance h₂ to achieve this speed.
Use the equation of motion,
Substitute 6.067 m/s for v, 0 m/s for u, 9.8 m/s² for a (=g) and h₂ for s.
The height h above the ground at which the acorn was is given by,
The acorn was at a height <u>4.15m</u> from the ground before dropping down.
Answer:
The work function ϕ of the metal = 53.4196 x 10⁻¹⁶ J
Explanation:
When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.
The relationship between the maximum kinetic energy () of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:
= h(f − f₀)
= hf - hf₀
E is the energy of the absorbed photons: E = hf
ϕ is the work function of the surface: ϕ = hf₀
= E - ϕ
Frequency f = 8.12×10¹⁸ Hz
Maximum kinetic energy = 4.16×10⁻¹⁷ J
Speed of light c = 3 x 10⁸ m/s
Planck's constant h = 6.63 × 10⁻³⁴ Js
E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸
E = 53.8356 x 10⁻¹⁶ J
from = E - ϕ ;
ϕ = E -
ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷
ϕ = 53.4196 x 10⁻¹⁶ J
The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J