Answer:
The intensity will be 1/9 as much.
Explanation:
The intensity of the light or any source is inversely related to the square of the distance.

Now according to the question the distance is increased by three times than,

Therefore,

Therefore the intensity will become 1/9 times to the initial intensity.
Answer:
d = 1.55 * 10⁻⁶ m
Explanation:
To calculate the distance between the adjacent grooves of the CD, use the formula,
..........(1)
The fringe number, m = 1 since it is a first order maximum
The wavelength of the green laser pointer,
= 532 nm = 532 * 10⁻⁹ m
Distance between the central maximum and the first order maximum = 1.1 m
Distance between the screen and the CD = 3 m
= Angle between the incident light and the diffracted light
From the setup shown in the attachment, it is a right angled triangle in which


Putting all appropriate values into equation (1)

The difference between the two is, well for one
Spectrum: The entire range that the "<em>waves" </em>could be such, as visible light, x-ray's and so on.
Waves: These are different because they aren't telling you or showing the entire spectrum just which they length that they are.
<em>It may confuse you but it makes sense to me (Sorry)</em>
(6) first choice: the frequency appears higher and wavelength is shorter.
The car approaches a stationary observer and so the sound will appear to have shorter wavelength. This creates an effect of its siren to sound with higher frequency than it would do if both were stationary.
(7) The Doppler formula for frequency in the case of a stationary observer and source approaching it is as follows:

The wavelength is then

The third choice "0.80m; 431Hz" is correct