Explanation:
(a)
Critical angle is the angle at the angle of refraction is 90°. After the critical angle, no refraction takes place.
Using Snell's law as:
Where,
is the angle of incidence
is the angle of refraction = 90°
is the refractive index of the refraction medium
is the refractive index of the incidence medium
Thus,
The formula for the calculation of critical angle is:
Where,
is the critical angle
(b)
No it cannot occur. It only occur when the light ray bends away from the normal which means that when it travels from denser to rarer medium.
Answer: D. it has been demonstrated to be without exception under certain stated conditions.
Explanation:
A <u>Law</u> is an affirmation (something established) based on repeated long-term observation of a phenomenon that has been studied and verified.
That is: A law is present in all known theories and therefore is considered universal. In addition, a law can not be refuted, nor changed, because its precepts have been proven through various studies.
<u>Unlike theory</u>, which is the set of rules and principles that describe and explain a particular phenomenon and <u>is subject to changes as new evidence emerges that gives meaning to it. </u>
Then, based on what is explained above, the law of universal gravitation is a statement that exists because it was rigorously tested and verified, therefore it can not be refuted.
Just because the book is moving doesn't tell you anything about the forces on it, or even whether there ARE any.
Just look at Newton's first law of motion, and this time, let's try and THINK about it too. It says something to the effect that any object continues in constant, uniform MOTION ..... UNLESS acted on by an external force.
Answer:
a) the strong magnetic field inhibits the currents of hot gas rising from below.
Explanation:
Sunspots are dark because they are a little cooler than the photo sphere.
The magnetic field inhibits the strong rising currents of hot gas,allowing it to cool the surface.
Answer:
The answer is "No, Hoverboards are risky, and riders are in danger of falling".
Explanation:
It's also known as a self-balanced scooter, it handheld electrical devices traveling on two wheels are hoverboards. It dominated the industry around 2015 and since then has become more and more successful. A rider is balanced on a frame between these wheels, driven by battery-powered lithium-ion batteries.