Advertisements
Advertisements
Question
An electromagnetic wave travelling along z-axis is given as: E = E0 cos (kz – ωt.). Choose the correct options from the following;
- The associated magnetic field is given as `B = 1/c hatk xx E = 1/ω (hatk xx E)`.
- The electromagnetic field can be written in terms of the associated magnetic field as `E = c(B xx hatk)`.
- `hatk.E = 0, hatk.B` = 0.
- `hatk xx E = 0, hatk xx B` = 0.
Options
a, b and c
a, c and d
b, c and d
b and d
Advertisements
Solution
a, b and c
Explanation:
a. The direction of propagation of an electromagnetic wave is always along the direction of vector product `vecE xx vecB`. Refer to figure.
`vecB = Bhatj = B(hatk xx hati) = E/c (hatk xx hati)`
= `1/c [k xx Ehati] = 1/c [hatk xx vecE]` .....`("as" E/B = c)`
b. `vecE = Ehati = cB(hatj xx hatk) = c(Bhatj xx hatk) = c(vecB xx hatk)`
c. `hatk * vecE = hatk * (Ehati)` = 0, `veck * vecB = hatk * (Bhatj)` = 0
d. `hatk xx vecE = hatk xx (Ehati) = E(hatk xx hati) = Ehatj` and `hatk xx vecB = hatk xx (Bhatj) = B(hatk xx hatj) = - Bhati`
APPEARS IN
RELATED QUESTIONS
A parallel plate capacitor (Figure) made of circular plates each of radius R = 6.0 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V ac supply with a (angular) frequency of 300 rad s−1.
- What is the rms value of the conduction current?
- Is the conduction current equal to the displacement current?
- Determine the amplitude of B at a point 3.0 cm from the axis between the plates.
The charging current for a capacitor is 0.25 A. What is the displacement current across its plates?
A capacitor has been charged by a dc source. What are the magnitude of conduction and displacement current, when it is fully charged?
A parallel-plate capacitor of plate-area A and plate separation d is joined to a battery of emf ε and internal resistance R at t = 0. Consider a plane surface of area A/2, parallel to the plates and situated symmetrically between them. Find the displacement current through this surface as a function of time.
Displacement current is given by ______.
If the total energy of a particle executing SHM is E, then the potential energy V and the kinetic energy K of the particle in terms of E when its displacement is half of its amplitude will be ______.
Displacement current goes through the gap between the plantes of a capacitors. When the charge of the capacitor:-
A parallel plate capacitor of plate separation 2 mm is connected in an electric circuit having source voltage 400 V. What is the value of the displacement current for 10-6 second if the plate area is 60 cm2?
According to Maxwell's hypothesis, a changing electric field gives rise to ______.
A capacitor of capacitance ‘C’, is connected across an ac source of voltage V, given by V = V0 sinωt The displacement current between the plates of the capacitor would then be given by ______.
The charge on a parallel plate capacitor varies as q = q0 cos 2πνt. The plates are very large and close together (area = A, separation = d). Neglecting the edge effects, find the displacement current through the capacitor?
Show that average value of radiant flux density ‘S’ over a single period ‘T’ is given by S = `1/(2cmu_0) E_0^2`.
You are given a 2 µF parallel plate capacitor. How would you establish an instantaneous displacement current of 1 mA in the space between its plates?
Sea water at frequency ν = 4 × 108 Hz has permittivity ε ≈ 80 εo, permeability µ ≈ µo and resistivity ρ = 0.25 Ω–m. Imagine a parallel plate capacitor immersed in seawater and driven by an alternating voltage source V(t) = Vo sin (2πνt). What fraction of the conduction current density is the displacement current density?
A particle is moving with speed v = b`sqrtx` along positive x-axis. Calculate the speed of the particle at time t = τ (assume that the particle is at origin at t = 0).
A parallel plate capacitor is charged by connecting it to a battery through a resistor. If I is the current in the circuit, then in the gap between the plates, there is no conduction current:
