Displacement current is the same as:
1. | Conduction current due to the flow of free electrons |
2. | Conduction current due to the flow of positive ions |
3. | Conduction current due to the flow of both positive and negative free charge carriers |
4. | It is not a conduction current but is caused by the time-varying electric field |
The maxwell's equation:
is a statement of :
(1) Faraday's law of induction
(2) Modified Ampere's law
(3) Gauss's law of electricity
(4) Gauss's law of magnetism
The charge of a parallel plate capacitor is varying as \(q = q_{0} \sin\omega t\). Find the magnitude of displacement current through the capacitor.
(Plate Area = \(A\), separation of plates = \(d\))
1. \(q_{0}\cos \left(\omega t \right)\)
2. \(q_{0} \omega \sin\omega t\)
3. \(q_{0} \omega \cos \omega t\)
4. \(\frac{q_{0} A \omega}{d} \cos \omega t\)
The rate of change of the voltage of a parallel plate capacitor if the instantaneous displacement current of 1 A is established between the two plates of a 1 F parallel plate capacitor:
1.
2. 10 V/s
3.
4.
The relation between electric field E and magnetic field induction B in electromagnetic waves is given by:
(1)
(2) E = cB
(3) E =
(4)
An electromagnetic wave is propagating along Y-axis. Then:
(1) The oscillating electric field is along X-axis and the oscillating magnetic field is along Y-axis.
(2) The oscillating electric field is along Z-axis and the oscillating magnetic field is along X-axis.
(3) Both oscillating electric and magnetic fields are along Y-axis, but the phase difference between them is
(4) Both oscillating electric and magnetic fields are mutually perpendicular in arbitrary directions.
In electromagnetic wave the phase difference between electric and magnetic field vectors \(\vec E~\text{and}~\vec B\) is:
1. \(0\)
2. \(\frac{\pi}{2}\)
3. \(\pi\)
4. \(\frac{\pi}{4}\)
An electromagnetic wave going through the vacuum is described by
Which is the following is/are independent of the wavelength?
1. | \(k\) | 2. | \(k \over \omega\) |
3. | \(k \omega\) | 4. | \( \omega\) |
In a plane EM wave, the electric field oscillates sinusoidally at a frequency of \(2.5\times 10^{10}~\text{Hz}\) and amplitude \(480\) V/m. The amplitude of the oscillating magnetic field will be:
1. \(1.52\times10^{-8}~\text{Wb/m}^2\)
2. \(1.52\times10^{-7}~\text{Wb/m}^2\)
3. \(1.6\times10^{-6}~\text{Wb/m}^2\)
4. \(1.6\times10^{-7}~\text{Wb/m}^2\)
If represent the permittivity and permeability of vacuum and represent the permittivity and permeability of the medium, then refractive index of the medium is given by :
(1) (2)
(3) (4)
The energy density of the electromagnetic wave in vacuum is given by the relation:
1.
2.
3.
4.
A lamp radiates power \(P_0\) uniformly in all directions. The amplitude of electric field strength \(E_0\) at a distance \(r\) from it is:
1. \(E_{0} = \frac{P_{0}}{2 \pi\varepsilon_{0} cr^{2}}\)
2. \(E_{0} = \sqrt{\frac{P_{0}}{2 \pi\varepsilon_{0} cr^{2}}}\)
3. \(E_{0} = \sqrt{\frac{P_{0}}{4 \pi\varepsilon_{0} cr^{2}}}\)
4. \(E_{0} = \sqrt{\frac{P_{0}}{8 \pi\varepsilon_{0} cr^{2}}}\)
The sun delivers of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimensions 8 m20 m will be
(1) (2)
(3) (4)
The intensity of visible radiation at a distance of \(1\) m from a bulb of \(100\) W which converts only \(5\%\) of its power into light, is:
1. \(0.4\) W/m2
2. \(0.5\) W/m2
3. \(0.1\) W/m2
4. \(0.01\) W/m2
On an EM wave, the amplitude of electric and magnetic fields are 100 v/m and 0.265 A/m. The maximum energy flow is
(1) 26.5 (2) 46.7
(3) 66.5 (4) 86.5
The most penetrating radiation out of the following is:
(1) X-rays (2) -rays (3) -rays (4) -rays
A. | \(X\text-\)rays in vacuum travel faster than light waves in vacuum. |
B. | The energy of an \(X\text-\)ray photon is greater than that of a light photon. |
C. | Light can be polarised but \(X\text-\)ray cannot. |
1. A and B
2. B and C
3. A, B and C
4. B only
The magnetic field in a plane EM wave traveling in the positive x-direction is given by
The equation for electric field is :
1. E=100sin [(2(t-x/c)]
2. E=(3)sin [(2(t-x/c)]
3. E=3sin [(2(t-x/c)]
4. E=100sin [(2(t-x/c)]
Statement I: A changing electric field produces a magnetic field.
Statement II: A changing magnetic field produces an electric field.
(1) If both statement-I and Statement-II are true, and Statement-II is the correct explanation of Statement-I.
(2) If both Statement-I and Statement-II are true but Statement-II is not the correct explanation of Statement-I.
(3) If Statement-I is true but Statement-II is false.
(4) If Statement-I is false but Statement-II is true.
Statement-I: Gamma rays are more energetic than X-rays.
Statement-II: Gamma rays are of nuclear origin but X-rays are produced due to sudden deceleration of high energy electrons while falling on a metal of high atomic number.
(1) If both statement-I and Statement-II are true, and Statement-II is the correct explanation of Statement-I.
(2) If both Statement-I and Statement-II are true but Statement-II is not the correct explanation of Statement-I.
(3) If Statement-I is true but Statement-II is false.
(4) If Statement-I is false but Statement-II is true.