Answer:
B
Explanation:
b/c air is not seen by eye
(1) 14C
(2) 37Ca
(3) 53Fe
(4) 42K
Answer:
an element is a pure substance
Explanation:
B
It changes direction when it passes through an opening
С
It changes its speed and wavelength when it passes through an opening
D
It changes direction when it passes from one medium to another
E
It changes its speed and wavelength from one medium to another.
F
It changes direction when it bounces off of a solid surface.
If a sound wave refracts,It changes its speed and wavelength when it bounces off of a solid surface,It changes its speed and wavelength when it passes through an opening, and It changes direction when it passes from one medium to another. Therefore, option A, C and D are correct.
An important case in which sound waves change form or spread out is called refraction. This phenomenon affects the bending of a sound wave owing to changes in the wave's speed.
Refraction is the reason ocean waves near a shore parallel to the beach and why glass lenses can be used to focus light waves.
If the air above the earth is warmed than that at the surface, sound will be change shape back downward toward the surface by refraction. Soundpropagates in all directions from a point source.
Thus, option A, C and D are correct.
To learn more about the refraction of sound wave, follow the link;
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what happened millions of years ago
the time prior to the use of written records
Answer:
False is your answer
The statement is false. The <ul> element is for unordered lists, while the <dl> elements along with <dt> and <dd> are used for description lists in HTML.
The statement that the grouping element, <ul>, contains the definition associated with a term from a description list is false. In HTML, the <ul> element is used to create an unordered list, typically represented by bullet points. The definitions associated with terms in a description or definition list are contained within a <dl> element. Within this <dl> element, each term is denoted by a <dt> (description term) element, and the corresponding definition is provided within a <dd> (description details) element. It's important to use these specific elements to ensure proper semantics and accessibility on the web.
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Answer:
It undergoes a physical change.
Explanation: