Is the center of each galaxy a black hole containing new galaxy?
1 answer:
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Answer:
2.11eV
Explanation:
We know that speed of light is it's wavelength times frequency.
Planck's constant is
The energy gap is calculated by multyplying the light's frequency by planck's constant:
Hence, the energy gap is 2.11eV
Answer:
for the birds to be able to stay vertical in flight without falling down to earth, they must produce a lift that will counteract their weight
for the small bee humming bird,
mass = 1.6 g = 1.6 x kg
weight of the bird under acceleration due to gravity = mg
where g = acceleration due to gravity = 9.81 m/s^2
weight of the bird = 1.6 x x 9.806 = 0.0156 ≅ 0.016 N
for this bird to maintain flight, the least lift upward, it must generate must be equal to its weight downwards, i.e
lift = weight
therefore,
lift = <em>0.016 N</em>
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For the bustard of Europe and Asia,
mass = 21 kg
weight of the bird under acceleration due to gravity = mg
weight of the bird = 21 x 9.806 = 205.9 N
lift = weight = <em>205.9 N</em>
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<em>lift generated is proportional to the wing surface area according to the lift equation</em>
L = Cs x p x x S
where L = lift
C = lift coefficient
p = density of air
v = relative velocity of bird and air
S = surface are of the wing.
<em>The great bustard will have a proportionally larger wing area to hold its weight in flight</em>
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Complete question:
Polystyrene has dielectric constant 2.6 and dielectric strength 2.0 × 10⁷ V/m . A piece of polystyrene is used as a dielectric in a parallel-plate capacitor, filling the volume between the plates.
a- When the electric field between the plates is 79 % of the dielectric strength, what is the energy density of the stored energy?
b- When the capacitor is connected to a battery with voltage 500.0 V , the electric field between the plates is 79 % of the dielectric strength. What is the area of each plate if the capacitor stores 0.25 mJ of energy under these conditions?
Answer:
(a) The energy density of the stored energy is 2872.1 J/m³
(b) Area of the plate is 27.51 cm²
Explanation:
Given;
dielectric constant, K = 2.6
dielectric strength = 2.0 × 10⁷ V/m
potential difference of the battery, V = 500 V
Part (a)
Electric field strength, E = 79 % of dielectric strength
E = 0.79 x 2.0 × 10⁷ V/m
E = 1.58 × 10⁷ V/m
The energy density of the stored energy
u = ¹/₂Kε₀E²
where;
u is the energy density
ε₀ is permittivity of free space = 8.85 x 10⁻¹² C²/N.m²
u = ¹/₂Kε₀E² = ¹/₂ x 2.6 x 8.85 x 10⁻¹² x (1.58 × 10⁷)²
u = 28.721 x 10² J/m³
u = 2872.1 J/m³
Part (b) Area of the plate if the capacitor stores 0.250 mJ of energy
The energy density of stored energy is also given as;
U = ¹/₂KC₀V², U = 0.250 mJ
The charge stored in the capacitor;
Substitute these values and solve for Area
A = 27.51 cm²