The only reasonable choice from this list is choice-A.
Answer: 1.28 sec
Explanation:
Assuming that the glow following the collision was produced instantaneously, as the light propagates in a straight line from Moon to the Earth at a constant speed, we can get the time traveled by the light applying velocity definition as follows:
V = ∆x / ∆t
Solving for ∆t, we have:
∆t = ∆x/v = ∆x/c = 3.84 108 m / 3.8 108 m/s = 1.28 sec
Helium has only 2 electrons in it's valence shell
So, option D is your answer.
Hope this helps!
<h2>
Answers: </h2>
1) 1.359, 1.403
2) 
, 
Explanation:
The described situation is known as Refraction.
Refraction is a phenomenon in which a wave (the light in this case) bends or changes it direction when passing through a medium with a refractive index different from the other medium.
In this context, the Refractive index 
is a number that describes how fast light propagates through a medium or material, and is defined as the relation between the speed of light in vacuum (
) and the speed of light 
in the second medium:
(1)
On the other hand we have the Snell’s Law:
(2)
Where:
is the first medium refractive index . We are told is the air, hence 
is the second medium refractive index
is the angle of the incident ray
is the angle of the refracted ray
Knowing this, let's begin with the answers:
<h2><u>1) Indexes of refraction for red and violet light</u></h2><h2 /><h2>1a) Red light</h2>
Using equation (2) according to Snell's Law and 
:
Finding :
(3)>>>Index of Refraction for red light
<h2>1b) Violet light</h2>
Again, using equation (2) according to Snell's Law and 
:
Finding :
(4) >>>Index of Refraction for violet light
<h2><u>2) Speeds of red and violet light</u></h2><h2 /><h2>1a) Red light</h2>
Here we are going to use equation (1):
Substituting (3) in this equation:
>>>>Speed of red light
<h2>1a) Violet light</h2>
Using again equation (1):
Substituting (4) in this equation:
>>>>Speed of violet light
<h2>Isaac Newton's First Law of Motion states, "A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force." What, then, happens to a body when an external force is applied to it? That situation is described by Newton's Second Law of Motion. </h2><h2>
equation as ∑F = ma
</h2><h2>
</h2><h2>The large Σ (the Greek letter sigma) represents the vector sum of all the forces, or the net force, acting on a body. </h2><h2>
</h2><h2>It is rather difficult to imagine applying a constant force to a body for an indefinite length of time. In most cases, forces can only be applied for a limited time, producing what is called impulse. For a massive body moving in an inertial reference frame without any other forces such as friction acting on it, a certain impulse will cause a certain change in its velocity. The body might speed up, slow down or change direction, after which, the body will continue moving at a new constant velocity (unless, of course, the impulse causes the body to stop).
</h2><h2>
</h2><h2>There is one situation, however, in which we do encounter a constant force — the force due to gravitational acceleration, which causes massive bodies to exert a downward force on the Earth. In this case, the constant acceleration due to gravity is written as g, and Newton's Second Law becomes F = mg. Notice that in this case, F and g are not conventionally written as vectors, because they are always pointing in the same direction, down.
</h2><h2>
</h2><h2>The product of mass times gravitational acceleration, mg, is known as weight, which is just another kind of force. Without gravity, a massive body has no weight, and without a massive body, gravity cannot produce a force. In order to overcome gravity and lift a massive body, you must produce an upward force ma that is greater than the downward gravitational force mg. </h2><h2>
</h2><h2>Newton's second law in action
</h2><h2>Rockets traveling through space encompass all three of Newton's laws of motion.
</h2><h2>
</h2><h2>If the rocket needs to slow down, speed up, or change direction, a force is used to give it a push, typically coming from the engine. The amount of the force and the location where it is providing the push can change either or both the speed (the magnitude part of acceleration) and direction.
</h2><h2>
</h2><h2>Now that we know how a massive body in an inertial reference frame behaves when it subjected to an outside force, such as how the engines creating the push maneuver the rocket, what happens to the body that is exerting that force? That situation is described by Newton’s Third Law of Motion.</h2><h2 />
