Answer:
Since then only three elements on the periodic table have been found to be ferromagnetic at room temperature - iron (Fe), cobalt (Co), and nickel (Ni). The rare earth element gadolinium (Gd) nearly misses by only 8 degrees Celsius.
Explanation:
Answer:
is reflected back into the region of higher index
Explanation:
Total internal reflection is a phenomenon that occurs when all the light passing from a region of higher index of refraction to a region of lower index is reflected back into the region of higher index.
According to Snell's law, refraction of ligth is described by the equation

where
n1 is the refractive index of the first medium
n2 is the refractive index of the second medium
is the angle of incidence (in the first medium)
is the angle of refraction (in the second medium)
Let's now consider a situation in which

so light is moving from a medium with higher index to a medium with lower index. We can re-write the equation as

Where
is a number greater than 1. This means that above a certain value of the angle of incidence
, the term on the right can become greater than 1. So this would mean

But this is not possible (the sine cannot be larger than 1), so no refraction occurs in this case, and all the light is reflected back into the initial medium (total internal reflection). The value of the angle of incidence above which this phenomen occurs is called critical angle, and it is given by

Answer:
the ratio of the angle subtended at the eye by the image formed by an optical instrument to that subtended at the eye by object when not viewed through the instrument.
During the ball's flight up its velocity and acceleration vectors are in opposite direction and during the ball's flight down its velocity and acceleration vectors are in same direction.
- The velocity vector is always in the direction of motion of the object. So, during the ball's flight up its velocity vector is in the upward direction (90°) and during the ball's flight down its velocity vector is in the downward direction (270°).
- When there is a positive acceleration in the object the acceleration vector is in the direction of motion of the object. When there is a negative acceleration in the object the acceleration vector is in the opposite direction of motion of the object. So, during the ball's flight up its acceleration vector is in the downward direction (270°) and during the ball's flight down its acceleration vector is in the upward direction (90°).
Velocity vector is the rate of change of position of an object. Acceleration vector is the rate of change of velocity of an object.
Therefore, during the ball's flight up its velocity and acceleration vectors are in opposite direction and during the ball's flight down its velocity and acceleration vectors are in same direction.
To know more about velocity and acceleration vectors
brainly.com/question/13492374
#SPJ4
There will be 0.125g (1/8th) left of that radioactive substance by 3:00pm
12:00 = 1g
1:00 = 0.5g
2:00 = 0.25g
3:00 = 0.125g