True or false: (a) Maxwell's equations apply only to fields that are constant over time.(b) The wave equation can be derived fro
1 answer:
Answer:
(a) False
(b) True
(c) True
(d) True
(e) True
(f) True
Explanation:
(a) Maxwell's equations not only applies to constant fields but it applies to both the fields, i.e., Time variant field as well as Time Invariant field.
(b) We make use of the Modified form of the Ampere's law and Faraday's Law to derive the wave equation.
(c) Electromagnetic waves contains both the electric and magnetic fields and these fields oscillates at an angle of to the direction of wave propagation.
(d) In free space both the electric and magnetic fields are in phase while considering electromagnetic waves.
(e) In free space or vacuum, the expression for the speed of light in terms of electric and magnetic field is given as:
Thus the ratio of the magnitudes of the electric and magnetic field vectors are equal to the speed of light in free space.
(f) In free space or in vacuum the energy density of the electromagnetic wave is divided equally in both the fields and hence are equal.
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Given:
The angle of projection of the basketball, θ=35°
The height at which the ball leaves the hand, h=7 ft
The initial velocity of the basketball, v=20 ft/s
To find:
The parametric equations describing the shot.
Explanation:
The range, x of the basketball is given by,
On substituting the known values,
The change in the height, y of the basketball is given by,
Where g is the acceleration due to gravity.
On substituting the known values,
Final answer:
The parametric equations describing the shot are
Answer:
The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field.
The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current.
The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.
Explanation:
The magnitude of the magnetic force exerted on a current-carrying wire due to a magnetic field is given by
(1)
where I is the current, L the length of the wire, B the strength of the magnetic field, the angle between the direction of the field and the direction of the current.
Also, B, I and F in the formula are all perpendicular to each other. (2)
According to eq.(1), we see that the statement:
<em>"The magnetic force on the current-carrying wire is strongest when the current is perpendicular to the magnetic field lines.</em>"
is correct, because when the current is perpendicular to the magnetic field, and the force is maximum.
Moreover, according to (2), we also see that the statements
<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the field. "</em>
<em>"The direction of the magnetic force acting on a current-carrying wire in a uniform magnetic field is perpendicular to the direction of the current. "</em>
because F (the force) is perpendicular to both the magnetic field and the current.