Answer:
The source is at a distance of 4.56 m from the first point.
Solution:
As per the question:
Separation distance between the points, d = 11.0 m
Sound level at the first point, L = 66.40 dB
Sound level at the second point, L'= 55.74 dB
Now,

where

I = Intensity of sound
Now,

Similarly,

Now,




Solving the above quadratic eqn, we get:
R = 4.56 m
Answer : 
Explanation :
Given that,
Charge of particle 1 = 
Distance x = 6 cm
Charge of particle 2 = 
Distance x = 27 cm
Total distance = 

Particle 1 is at (6,0) and particle 2 is at (27,0) .
Therefore, midway (16.5, 0)
Now, 
Formula of electric field

Now, the the electric field due to particle 1



Similarly, the electric field due to particle 2

Resultant Electric field


Hence, this is the required answer.
The change in surface area of Gaussian surface with radius (r) is 8πr.
<h3>
Electric field from Coulomb's law</h3>
The electric field experienced by a charge is calculated as follows;

where;
- E is the electric field
- Q is the charge
- r is the radius
The electric field reduces by a factor of 
<h3>Surface area of a Gaussian surface;</h3>
The surface area of a sphere is given as;

<h3>Change in area with r</h3>

Thus, the change in surface area of Gaussian surface with radius (r) is 8πr.
Learn more about area of Gaussian surfaces here: brainly.com/question/17060446
Answer: 0.8 m
Explanation:
Velocity of throw = 4m/s
Maximum Height attained(h) =?
Downward acceleration experienced = 10m/s^2
Using the relation:
v^2 = u^2 + 2aS
v = final Velocity = 0 (at maximum height)
u = Initial Velocity = 4
a = g downward acceleration = - 10
0 = 4^2 + 2(-10)(S)
0 = 16 - 20S
20S = 16
S = 16 / 20
S = 0.8m
Maximum Height attained = 0.8m