Answer:
f1 = 12.90 Hz
Explanation:
To calculate the first harmonic frequency you use the following formula for n = 1:

( 1 )
It is necessary that the unist are in meters, then you have:
L: length of the string = 60cm = 0.6m
M: mass of the string = 0.05kg
T: tension on the string = 20 N
you replace the values of L, M and T in the expression (1) for getting f1:

Hence, the first harmonic has a frequency of 12.90 Hz
Answer:
The farther star will appear 4 times fainter than the star that is near to the observer.
Explanation:
Since it is given that the luminosity of the 2 stars is same thus they radiate the same energy per unit time
Consider a spherical wave front of energy 'E' that leaves both the stars (Both radiate 'E' as they have same luminosity)
This Energy is spread over the whole surface area of sphere Thus when the wave front is at a distance 'r' the energy per unit surface area is given by

For the star that is twice away from the earth the distance is '2r' thus we will receive an energy given by
Hence we sense it as 4 times fainter than the nearer star.
Work done is equal to force by distance; so you take the force exerted, in newtons, and multiply that by the direction it's moved (from the starting point in a line, not along the path it's taken.)
Answer:
- path differnce = 2.18*10^-6
- 1538 lines
Explanation:
- The path difference for the waves that produce the pattern of diffraction, is given by the following formula:
(1)
d: separation between slits = 0.50mm = 0.50*10^-3 m
θ: angle of a diffraction = 0.25°
Then, the path difference is:

- The maximum number of bright lines are calculated by using the following formula:
(2)
m: order of the bright
λ: wavelength = 650nm
The maximum bright is calculated for an angle of 90°:

The maxium number of bright lines are twice the previous result, that is, 1538 lines
Answer:
The distance from the Sun to Neptune is 29,41 AU.
Explanation:
We know, from the sentence, that the orbit of Neptune has an average diameter around 8.80*10⁹km.
Now, we can calculate the radius of this orbit, which is equivalent to the distance from thsi planet to the Sun. Let's recall tha the radius is the half of the diameter.

Ok, we know that 1.496*10¹¹m is an AU, therefore we have:

Finally, the distance R is 29,41 AU.
I hope it helps you! :)