All categories

3 years ago

What does the principle of the constancy of lightspeed tell us about the speed of light?

Physics

1 answer:

Thepotemich [5.8K]3 years ago

7 0

Answer:

The speed of light is not relative, it is always c no matter how fast or in what way the observer is moving

Explanation:

The speed of light. In a vacuum, it is by definition a universal constant of value 299,792,458 m / s (usually close to 3 · 108 m / s), or what is the same 9.46 · 1015 m / year; The second figure is used to define the interval called the light year. It is symbolized by the letter c, from the Latin celéritās (in Spanish celerity or rapidity), and is also known as the Einstein constant. [Citation needed] The value of the speed of light in a vacuum was officially included in the System International Units as a constant on October 21, 1983, thus passing the meter to be a unit derived from this constant. The speed through a medium other than the "vacuum" depends on its electrical permittivity, its magnetic permeability, and other electromagnetic characteristics. In material media, this speed is lower than "c" and is encoded in the index of refraction. In more subtle vacuum modifications, such as curved spaces, Casimir effect, thermal populations or presence of external fields, the speed of light depends on the energy density of that vacuum .

You might be interested in

Rory uses a force of 25 N to lift her grocery bag while doing 50 J of work. How far did she lift the

Dennis_Churaev [7]

Answer:

$W=Fd \\ 50 = 25d \\ d = \frac{50}{25} \\ \color{yellow} \boxed{d = 2m}$

8 0

3 years ago

Which of the following is NOT a level of home monitoring?

Bingel [31]

<h2>Answer:</h2>

d. electronic monitoring

<h2>Explanation:</h2>

Home monitoring in its simplest term is the act of restricting the movement of an entity, object or an individual to a specified location, usually their homes.

In criminology, there are various levels of home monitoring. Some of them are;

i. <em>Curfew</em>: This type of home monitoring requires that the persons being monitored be indoors/at home at specified hours.

ii. <em>Home incarceration</em>: This level of home monitoring requires that the persons being monitored be indoors/at home at all times except in times of medical urgencies.

iii. <em>Home detention</em>: This seems to be one of the less strict forms of home monitoring. It requires that the persons being monitored be indoors/at home at all times except when necessary. For example, they could go to school, their workplace, to the market and so on.

Electronic monitoring is not a form of home monitoring as it allows the person being monitored to move freely. They might just contacted via telephone or any other means, at intervals to know their whereabouts.

5 0

2 years ago

What evidence do we have that Earth has a magnetic field surrounding the planet?

Ber [7]

A compass works the way it does because Earth has a magnetic field that looks a lot like the one in a magnet. The Earth's field is completely invisible, but it can be felt by a compass needle on the Earth's surface, and it reaches thousands of miles out into space.

5 0

3 years ago

Read 2 more answers

The nonreflective coating on a camera lens with an index of refraction of 1.21 is designed to minimize the reflection of 570-nm

lord [1]

Answer: 117.8 nm

Explanation:

Given,

Nonreflective coating refractive index : n = 1.21

Index of refraction: $n_0$ = 1.52

Wave length of light = λ = 570 nm = $570\times10^{-9}\ m$

$\text{ Thickness}=\dfrac{\lambda}{4n}$

$=\dfrac{570\times10^{-9}\ m}{4\times1.21}\\\\\approx\dfrac{117.8\times 10^{-9}\ m}{1}\\\\=117.8\text{ nm}$

Hence, the minimum thickness of the coating that will accomplish= 117.8 nm

5 0

3 years ago

Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa

ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

$v^2 - u^2 = 2*a*s$

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

$v^2 - 0 = 2 * 12.501 * 10$

$v = 15.812 m/s$

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.

5 0

3 years ago