<h2>Answer: Ultraviolet Light
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Ultraviolet light, whose wavelength is approximately between 100 nm and 380 nm; is a type of electromagnetic radiation that is not visible to the human eye.
This light is used for many purposes, among which is the identification of fluerescent minerals.
In this sense, fluorescence is a property that certain materials have in which they absorb energy in the form of short wavelength not visible electromagnetic radiation (the ultraviolet, for example) and then emit some of that energy in the form of longer wavelength electromagnetic radiation (in the visible spectrum). This is also called luminiscence.
Hence, the correct option is a.
Answer:
254
Explanation:
use the formula "final Velocity- initial velocity / time = acceleration"
so "X - 14 /4 = 60"
60 x 4 = X - 14
240 +14 = X
X = 254
Explanation:
The dimension of the book is 1.75 m × 2.25 m. If the book ends up at its initial position. The displacement of the book is equal to zero as the object reaches to its initial position.
If it completes its motion in 23 s, t = 23 s
Total displacement of the book is equal to its perimeter. It is given by :

The net displacement divided by total time taken is called the average velocity of an object. Here, the displacement is 0. So, average velocity is 0.
The average speed of an object is given by :


v = 0.347 m/s
So, the average speed of the book is 0.347 m/s. Hence, this is the required solution.
No. They are different. The bird's distance for that period of time is double the height of the nest above the ground. His displacement for the same time is zero ... the length between the start point and end point.
Answer: Yes
Air serves as a propagation medium.
Explanation:
Propagation of sound wave require a medium for transmission. Sound is produced by vibrating objects, The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Therefore to propagate sounds (human voice) from one end of a lecture hall to the other we need a propagation medium which is air. Air serves as a propagation medium.