Answer:
the frequency of the second harmonic of the pipe is 425 Hz
Explanation:
Given;
length of the open pipe, L = 0.8 m
velocity of sound, v = 340 m/s
The wavelength of the second harmonic is calculated as follows;
L = A ---> N + N--->N + N--->A
where;
L is the length of the pipe in the second harmonic
A represents antinode of the wave
N represents the node of the wave

The frequency is calculated as follows;

Therefore, the frequency of the second harmonic of the pipe is 425 Hz.
Explanation :
According to astronomers, the whole universe is started with a giant explosion called as Big Bang. Big Bang theory shows that the universe is extended from high density state.
There are some evidence for big bang as :
(1) There are some red shifts of different galaxies which means that the universe is expanding.
(2) Due to the expanding of universe, some of the new elements are created like hydrogen, deuterium etc.
(3) Microwaves are detected by orbiting detectors.
All this parameters shows that big bang theory was correct.
The power of is series combination is Vn^2 times that of a parallel combination.
For series combination :
Req = R + R + R + ............... n times = nR
I = Δv/nr
Power = (Δv/nr)^2 × nr = Δv^2/nr
For parallel combination
1/req = 1/R + 1/R + 1/R +................(n times) = n/R
Req = R/n
Power = Δv/(R/n) = nΔv^2/R
Ratio = Δv^2/nr/n·Δv^2/R = 1/n^2
Hence, power of is series combination is Vn^2 times that of a parallel.
Learn more about parallel combination here:
brainly.com/question/12400458
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Answer: the pair of sunglasses
Explanation:
A good pair of sunglasses are composed of abosorbent lenses that filter the sunlight that affects the eyes retina, especially ultraviolet (UV). So, these sunglasses are used to reduce the amount of light or radiant energy transmitted.
On the other hand, normal reading glasses (in which the lens glass has not been treated to filter ultraviolet sunlight) will let UV rays pass through.
Therefore, if both glasses are exposed to sunlight, the sunglasses are expected to be warmer by absorbing that radiant energy and preventing it from reaching the eyes.
The way I do it is suddenly, in the same sort of way that magicians try to pull a table cloth off a table when there's things on the table cloth.The sudden approach acts as an impulse of force and starts to accelerate the roll. But, the piece (assuming it has perforations) is off the roll before the roll can move, due to inertia. Then the roll will acclerate, move, slow down and stop. However, in accelerating, the roll will unravel. The bigger the impulse the more it will unravel.+++++++++++++++++++++++++++++++++++++++If on the other hand, the piece of paper is held firmly, and the roll is pulled, then the impulse is presumably given to the paper and the hand whose inertia is a lot more than that of the roll. So, I think I'd actually go for choice c)+++++++++++++++++++++++++++++++++++++This assumes that the roll is free to rotate.I think that a similar idea is behind the design and use of a "ballistic galvanometer". The charge is passed through the galvanometer quickly, as a current pulse. Then the needle starts to deflect, and the deflection is arranged to depend on the total charge that has passed through in the time of the current pulse.