To
solve this problem, we assume that the wavelength of the light in air is 500
nanometers.
For this case we
only need the refractive index of the polystyrene. For an antireflective
coating, we need a quarter of wave thickness at the wavelength in the air. Which
means that the antireflective coating needs to be as thick as 1/4 of the
wavelength, divided by the coating’s refractive index. This is expressed
mathematically in the form:
x = λ / (4 * n)
where,
x = thickness
λ = wavelength
of light
n = index of
refraction of polystyrene
Substituting:
x = 500 nm / (4
* 1.49)
x = 500 nm / 5.96
x = 83.90 nm
Answer:
825 kgm⁻³
Explanation:
ρ = density of wood = ?
ρ' = density of water = 1000 kgm⁻³
V = volume of wood = 10 x 4 x 2 = 80 cm³ = 80 x 10⁻⁶ m³
V' = Volume of water displaced = 10 x 4 x 1.65 = 66 cm³ = 66 x 10⁻⁶ m³
Using equilibrium of force in vertical direction
Force of buoyancy = Weight of the wood
ρ' V' g = ρ V g
ρ' V' = ρ V
(1000) (66 x 10⁻⁶) = ρ (80 x 10⁻⁶)
ρ = 825 kgm⁻³
Given:
Therefore, the acceleration is,
<h3>
Explain Acceleration?</h3>
An object's rate of changing its velocity is known as its acceleration, which is a vector quantity. If an object's velocity is changing, it is accelerating. When anything moves faster or slower in a straight line, it is said to have been accelerated. Even if the speed is constant, motion on a circle accelerates because the direction is always shifting.
To learn more about Acceleration, visit:
brainly.com/question/12550364
#SPJ4
Answer:
- Direct current is a current in which electrons flow in one direction only
- Alternating current is a current in which the direction of the electron flow reverses periodically - so, half a cycle forward, half a cycle backward
There are several advantages of using alternating currents for the transmission of electricity across a country, over large distances. The main advantages are:
- The voltage of alternating currents can be easily increased/decreased by using transformers. For instance, a transformer is used at the beginning of the transmission line to increase the voltage (electricity is transmitted at high voltage in order to reduce dissipated power), and then another transformer is used before the electricity enters the houses, in order to decrease the voltage. Transformers only work with alternating currents.
- It is easy to interrupt the flow of an alternating current, because its value naturally becomes zero every half a cycle, so this is useful in case the current must be interrupted.
Answer:
38%
Explanation:
The following data is obtained from water property tables:
Part a)