Answer:
The planets spun in epicycles.
Explanation:
The planets were not simply attached to a mystical sphere (“deferent”) but they were actually attached to a mini-sphere (“epicycle”) which rotated on the larger one.
Answer:
Wavelength = 3.74 m
Explanation:
In order to find wavelength in "metres", we must first convert megahertz to hertz.
1 MHz = 1 × 10⁶ Hz
80.3 Mhz = <em>x</em>
<em>x </em>= 80.3 × 1 × 10⁶ = 8.03 × 10⁷ Hz
The formula between wave speed, frequency and wavelength is:
v = fλ [where v is wave speed, f is frequency and λ is wavelength]
Reorganise the equation and make λ the subject.
λ = v ÷ f
λ = (3 × 10⁸) ÷ (8.03 × 10⁷)
λ = 3.74 m [rounded to 3 significant figures]
Answer:
The work done is 0.
Explanation:
The reason no work is done is because the equation W = Fs.
W = work
F= force
s= displacement
In this scenario F = 50 and s= 0
Therefore.
W = 50(0)
W = 0
Answer
Correct answers are 1.an increase or decrease in pressure 2.an increase or decrease in energy
Explanation
All existing matter can undergo phase change it means they may transform from one state to another. phase change of a matter may occur due to change in energy and change in pressures.
for example there is an ice cube which is a solid and if we want to change it phase into liquid water for that purpose we have to supply some energy to ice cube it means we have to give some heat to ice cube. After supplying heat energy to the ice it will turn into water it means there is phase change from solid to liquid due to supplying the heat. Similarly we can change the liquid water into solid ice cube by taking heat energy(reducing temperature) from the liquid water .
In some cases the matter doesn't want to undergo phase transformation. For example, oxygen will solidify at -361.8 degrees Fahrenheit at standard pressure.But , it can change to solid state at warmer temperatures when the pressure is increased.
Answer:
The angle of incidence is greater than the angle of refraction
Explanation:
Refraction occurs when a light wave passes through the boundary between two mediums.
When a ray of light is refracted, it changes speed and direction, according to Snell's Law:
where
:
is the index of refraction of the 1st medium
is the index of refraction of the 2nd medium
is the angle of incidence (the angle between the incident ray and the normal to the boundary)
is the angle of refraction (the angle between the refracted ray and the normal to the boundary)
In this problem, we have a ray of light passing from air into clear plastic. We have:
(index of refraction of air)
approx. (index of refraction in clear plastic)
Snell's Law can be rewritten as
And since 
, we have
And so
Which means that
The angle of incidence is greater than the angle of refraction
