From the choices given, ultraviolet rays is a type electromagnetic radiation that causes certain substances to fluoresce. It cannot be detected by the naked eye but some insects are able to see them.
Like in a fluorescent light bulb, ultraviolet or UV lights stimulates the coating of the tube to emit light.
The Results For Earth's Circumcised were quite accurate. the diameter of earth is 12,740 km, the length of the stadium would be 1,140 km.
There are two rules of reflection for the concave mirror:
1)<span>Any incident ray traveling parallel to the principal axis on the way to the mirror will pass through the focal point upon reflection.
2)</span><span>Any incident ray passing through the focal point on the way to the mirror will travel parallel to the principal axis upon reflection.
Also, keep in that for concave mirror center of curvature is 2f.
Using these two rules we can construct the image.
You should always use these two "special" rays, I will mark then 1 and 2 on the picture.
From the picture, we can see that if you place the object between the focus and vertex you get the virtual image.
The answer is: object should be between the focal point and the vertex</span>
The frequency produced by the string could be 437 Hz or it could be 443 Hz.
The frequency of the beats ... 3 Hz ... tells the piano tuner that
the difference between the fork and string frequencies is 3 Hz,
but it doesn't tell her which one is higher or lower.