Answer:
Lightning
Explanation:
Air is a non-conductor of electricity because it does not have free electrons to carry the current. But when there is a high voltage, as in the case of lightning, the molecules of air get ionized and electrons are available to flow to make the current and conduct electricity through the air.
B. It decreases your resting heart rate
Hi there!
We can use the following equation to calculate the magnetic field inside of a solenoid:
B = Magnetic Field Strength (T)
n = number of loops PER LENGTH
i = current through solenoid (A)
μ₀ = Permeability of free space (4π × 10⁻⁷ Tm/A)
First, we can solve for 'n' given 'N' (total # of loops) and L (length of solenoid).
Now, we can calculate the magnetic field:
D = 497.4x10⁻⁶m. The diameter of a mile of 24-gauge copper wire with resistance of 0.14 kΩ and resistivity of copper 1.7×10−8Ω⋅m is 497.4x10⁻⁶m.
In order to solve this problem we have to use the equation that relates resistance and resistivity:
R = ρL/A
Where ρ is the resistivity of the matter, the length of the wire, and A the area of the cross section of the wire.
If a mile of 24-gauge copper wire has a resistance of 0.14 kΩ and the resistivity of copper is 1.7×10⁻⁸ Ω⋅m. Determine the diameter of the wire.
First, we have to clear A from the equation R = ρL/A:
A = ρL/R
Substituting the values
A = [(1.7×10⁻⁸Ω⋅m)(1.6x10³m)]/(0.14x10³Ω)
A = 1.9x10⁻⁷m²
The area of a circle is given by A = πr² = π(D/2)² = πD²/4, to calculate the diameter D we have to clear D from the equation:
D = √4A/π
Substituting the value of A:
D = √4(1.9x10⁻⁷m²)/π
D = 497.4x10⁻⁶m
This is quite an opinonated question because everyone learns and retains information differently. For me personally, I learn best in physics by doing lots and lots and LOTS of practice problems. the more repetition you get with the material the easier it will be for you to tackle problems quickly. The repetitive practice will also stick the equations in your head for a very long time. Hope this helped! I wish you the best of luck on your exam!