Answer:
The minimum frequency is 702.22 Hz
Explanation:
The two speakers are adjusted as attached in the figure. From the given data we know that
=3m
=4m
By Pythagoras theorem

Now
The intensity at O when both speakers are on is given by

Here
- I is the intensity at O when both speakers are on which is given as 6

- I1 is the intensity of one speaker on which is 6

- δ is the Path difference which is given as

- λ is wavelength which is given as

Here
v is the speed of sound which is 320 m/s.
f is the frequency of the sound which is to be calculated.

where k=0,1,2
for minimum frequency
, k=1

So the minimum frequency is 702.22 Hz
Answer:

Explanation:
The rotated angle is given by:

Since this is a quadratic equation it can be solved using:

Rewriting our equation:


Since
we discard the negative solution.

Answer:
a = 2.275 10⁻⁴ m
Explanation:
This is a diffraction problem that is described by the equation
a sin θ = m λ
The first dark minimum occurs for m = 1
a = λ / sin θ
The angle can be found by trigonometry,
tan θ = y / x
θ = tan⁻¹ y / x
Let's reduce the magnitudes to the SI system
y = 8.24 mm = 8.24 10⁻³ m
λ = 625 nm = 625 10⁻⁹ m
θ = tan⁻¹ 8.24 10⁻³ / 3.00
θ = 0.002747 rad
We calculate
a = 625 10⁻⁹ / sin 0.002747
a = 2.275 10⁻⁴ m
Farmula 2gh=vf²-vi²
2×0.42×9.81=0²-vi²
8.2404=vi²
Vi=✓8.2404
Vi=2.87m/sec
Is is the second one. 336 k. 273.15K= 0C.