Answer:
a. passing from south end of solenoid to north end and is decreasing in magnitude
Explanation:
by taking into account the Lenz's law
From the Lenz's law we know that if the self-induced emf is due to a decrease in the current, the self-induced current is in a opposite direction. In the other case, when the current increase, the self-induced current is in the same direction that the initial current in the solenoid.
If we assume the second case (the current is increasing) the change in the magnetic flux is negative and the self-induced current contributes to the initial current
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Answer:
the charge per unit area on the plastic sheet is - 3.23 x 10⁻⁷ C/m²
Explanation:
given information:
styrofoam mass, m = 16 g = 0.016 kg
net charge, q = - 8.6 μC
to calculate the charge per unit area on the plastic sheet, we can use the following equation:
where
the force between the electric field
m = mass
g = gravitational force
where
q = charge
E = electric field
and
E = σ/2ε₀
where
ε₀ = permitivity
thus
mg = qσ/2ε₀
σ = (2mg ε₀)/q
= 2 (0.016) (9.8) (8.85 x 10⁻¹²)/( - 8.6 x 10⁻⁶)
= - 3.23 x 10⁻⁷ C/m²
Answer:
c. the speed of a planet is greatest when it is closest to the Sun.
Explanation:
Johannes Kepler was an astronomer who discovered that planets had elliptical orbits in the early 1600s (between 1609 and 1619).
The three (3) laws published by Kepler include;
I. The first law of planetary motion by Kepler states that, all the planets move in elliptical orbits around the Sun at a focus.
II. According to Kepler's second law of planetary motion, the speed of a planet is greatest when it is closest to the Sun.
Thus, the nearer (closer) a planet is to the Sun, the stronger would be the gravitational pull of the sun on the planet and consequently, the faster is the speed of the planet in terms motion.
III. The square of any planetary body's orbital period (P) is directly proportional to the cube of its orbit's semi-major axis.
The current is defined as the amount of charge Q that passes through a certain point of a wire in a time
:
But the charge Q flowing in the wire is just the charge of a single electron, e, times the number of electrons N:
so the current can be rewritten as
Using
,
(charge of one electron), and
, we find the current:
Therefore correct answer is A).
Answer:
When the spectral lines are absorption lines, the effect is called inverse Zeeman effect.