A solar eclipse occurs when the moon crosses in front of the Sun, blocking some or all of its rays. A lunar eclipse happens when the moon is directly behind the earth, blocking the moon from receiving light. The only light comes from the light on earth's reflected shadow.
You can look at a lunar eclipse because there is very little light or none at all. You can't look at a solar eclipse because you are looking directly at the sun unless it is complete. Before totality, only some of the Sun is blocked, causing your pupils dilate to let in more light. Since they do this, more of the Sun's rays can be let in to the eye, which effectively allows your eyes to burn.
Some doctors and eye care specialists say that after someone complains of blindness after looking at a solar eclipse unaided, they can see what the Sun and moon looked like at the time that they looked at it, as it is burned onto their retinas.
Answer:
If all these three charges are positive with a magnitude of
each, the electric potential at the midpoint of segment
would be approximately
.
Explanation:
Convert the unit of the length of each side of this triangle to meters:
.
Distance between the midpoint of
and each of the three charges:
Let
denote Coulomb's constant (
.)
Electric potential due to the charge at
:
.
Electric potential due to the charge at
:
.
Electric potential due to the charge at
:
.
While forces are vectors, electric potentials are scalars. When more than one electric fields are superposed over one another, the resultant electric potential at some point would be the scalar sum of the electric potential at that position due to each of these fields.
Hence, the electric field at the midpoint of
due to all these three charges would be:
.
Acceleration = force / mass.
A = 100/50 = 2 m/s^2 .
Il existe troi types de rayons produits lors de la désintégration des éléments radioactifs:
-- "particules alpha" . . . noyaux d'hélium, composés chacun de 2 protons et 2 neutrons
-- "rayons bêta" ou "particules bêta" . . . flux d'électrons
-- "rayons gamma" . . . rayonnement électromagnétique avec les longueurs d'onde les plus courtes connues et l'énergie la plus élevée
<em>weight = (mass) x (gravity)</em>
Weight = (5.00 kg) x (9.81 m/s²)
weight = (5.00 x 9.81) (kg-m/s²)
<em>Weight = 49.05 Newton</em>