What happens to the density of ocean water when salinity increases? A. It increases. B. It decreases. C. It becomes variable. D.
1 answer:
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Answer:
1) current = I
2) Resistance = V/I
3) current = 2I
4) resistance = V/2I
5) current = 3I
6) Resistance = V/3I
7) Current = 4I
8) Resistance = V/4I
Explanation:
When one bulb is connected across the battery then let say the current is given as I
Then resistance is given as
When two bulbs are in parallel with the battery then
total current becomes twice of initial current
so we have
current = 2I
Resistance of the circuit is now
When three bulbs are in parallel with the battery then
total current becomes three times of initial current
so we have
current = 3I
Resistance of the circuit is now
When four bulbs are in parallel with the battery then
total current becomes four times of initial current
so we have
current = 4I
Resistance of the circuit is now
Answer:
L = μ₀ n r / 2I
Explanation:
This exercise we must relate several equations, let's start writing the voltage in a coil
= - L dI / dt
Let's use Faraday's law
E = - d Ф_B / dt
in the case of the coil this voltage is the same, so we can equal the two relationships
- d Ф_B / dt = - L dI / dt
The magnetic flux is the sum of the flux in each turn, if there are n turns in the coil
n d Ф_B = L dI
we can remove the differentials
n Ф_B = L I
magnetic flux is defined by
Ф_B = B . A
in this case the direction of the magnetic field is along the coil and the normal direction to the area as well, therefore the scalar product is reduced to the algebraic product
n B A = L I
the loop area is
A = π R²
we substitute
n B π R² = L I (1)
To find the magnetic field in the coil let's use Ampere's law
∫ B. ds = μ₀ I
where B is the magnetic field and s is the current circulation, in the coil the current circulates along the length of the coil
s = 2π R
we solve
B 2ππ R = μ₀ I
B = μ₀ I / 2πR
we substitute in
n ( μ₀ I / 2πR) π R² = L I
n μ₀ R / 2 = L I
L = μ₀ n r / 2I