Answer:
The new intensity decreases by a factor of 16.
Explanation:
The intensity of sound wave is given by :

P is power
A is area

or
, r is distance from the source
If the distance from the source is increased by a factor of 4, r' = 4r
So,

So, the new intensity decreases by a factor of 16.
The correct answer is
<span>A. decreasing the current
In fact, the magnetic field produced by a current carrying wire is given by
</span>

<span>where
</span>

is the vacuum permeability
<span>I is the current in the wire
r is the distance from the wire at which the field is calculated
We see from the formula that the intensity of the field, B, is directly proportional to the current I, so if the current decreases, the magnetic field strength B decreases as well.</span>
Ohm's law states that: 
Explanation:
Ohm's law states that in a conductor, the potential difference across the conductor is directly proportional to the current flowing through it. Mathematically,

where
V is the potential difference
I is the current
The constant of proportionality is called resistance (R), and it gives a measure of "how much the conductor opposes" to the flow of current. Therefore Ohm's law can be rewritten as

where R is the resistance. By rewriting the equation as

we see that the larger the resistance, the lower the current in the conductor.
Learn more about Ohm's law:
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Sound spreads through some kind of medium. Most of the time the medium is usually air. Sound can go through walls, like when you are playing really loud music and the neighbors tell you its to loud, you can't block it because it can travel through objects. Light does not need a medium to travel with. if you put a light in a room with no windows and no cracks, and you seal off the door the light can't escape that room, but if you did the same thing with sound it would travel trough the walls.
Answer:
a. 900 J
b. 0.383
Explanation:
According to the question, the given data is as follows
Horizontal force = 150 N
Packing crate = 40.0 kg
Distance = 6.00 m
Based on the above information
a. The work done by the 150-N force is


= 900 J
b. Now the coefficient of kinetic friction between the crate and surface is


= .383
We simply applied the above formulas so that each one part could calculate