The relationship between resistance R and resistivity
is
where L is the length of the wire and A its cross section.
The radius of the wire is half the diameter:
and the cross section is
From the first equation, we can then find the length of the wire when
(copper resistivity:
)
When light hits the boundary between two different materials, it can undergo both reflection and refraction.
Reflection is the change in the direction of the
wave that strikes the boundary between two materials.<span> It involves a change in the direction of waves when they clash with an obstacle.
Refraction involves the change in the direction of waves as they move from one medium to </span><span><span>another followed</span></span><span> by a change in speed and wavelength (this second medium should have different permitivity for the light to change its initial properties.)</span>
The working equation for this one is:
E = F/Q, where E is the strength of the electric field, F is the electric force and Q is the charge. Substituting the corresponding values, the strength of the electric field is equal to
E = -30 nN/-3 nC
E = 10 nN/nC
Answer:
One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.
Explanation:
This hypothesis is based on the fact that the speed of sound in air is v = 343 m / s with a small variation with temperature.
The speed of sound in solid soil is an average of the speed of its constituent media, giving values between
wood 3900 m / s
concrete 4000 m / s
fabrics 1540 m / s
earth 5000 m / s wave S
ground 7000 m / s P wave
we can see that the speed on solid earth is an order of magnitude greater than in air.
One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.
From the initial information, the wave going through the ground should arrive first.
