The answer is definitely A. A transparent material is a material that allows light to pass through it and can be seen through. A glass jar can be seen through. Some people might say B, which is a mirror, but a mirror cannot be seen through, it only shows reflection. Hope i helped. Have a nice day and Happy New Year.
Frequency and wavelength are inversely related. That is, when frequency increases, the value of the wavelength decreases and vice versa. The constant of proportionality of the relation is the speed of light that has a value of 3.0x10^8 m/s. We calculate as follows:
wavelength = speed of light /frequency
488x10^-9 = 3.8x10^8 / frequency
frequency = 6.15x10^14 /s = 6.15x10^14 Hz ------> OPTION 3
Answer:
The focal length fe of the eyepiece is <em>2.86 cm</em>
Explanation:
Since we are given the telescope's magnification and the length of the tube, we can use the expressions
<em>M = f_o/fe (1)</em> and
<em>l = f_o + fe (2)</em>
where
- M is the telescope's magnification
- l is the length of the tube
- fe is the focal length of the eye-piece
Rearranging equation (2) to make f_o the subject of the formula, we get
<em>f_o = l - fe</em>
Substituting the above equation into equation (1) we get
<em>M = (l - fe)/fe ⇒ fe = l/(M +1)</em>
<em> ⇒ fe = 60/(20 + 1)</em>
⇒ <em>fe = 2.86 cm</em>
Answer:
They could damage hearing
Explanation:
They can cause physical harm which is a risk
