The energy of the X-rays photon is 3.3J. Its frequency is :
(1)
(2)
(3)
(4)
A plane electromagnetic wave
propagates in a medium of dielectric constant
(1) 1.5
(2) 2.0
(3) 2.4
(4) 4.0
The magnetic field between the plates of radius 12 cm separated by a distance of 4 mm of a parallel plate capacitor of capacitance 100 pF along the axis of plates having conduction current of 0.15 A is
(1) zero
(2) 1.5 T
(3) 15 T
(4) 0.15 T
A larger parallel plate capacitor, whose plates have an area of \(1~\text{m}^2,\) separated from each other by \(1\) mm, is being charged at a rate of \(25.8\) V/s.
If the plates have dielectric constant \(10\), then the displacement current at this instant is:
1. \(25~\mu\text{A}\)
2. \(11~\mu\text{A}\)
3. \(2.2~\mu\text{A}\)
4. \(1.1~\mu\text{A}\)
A parallel plate capacitor with plate area \(A\) and separation between the plates \(d\), is charged by a source having current \(i\) at some instant. Consider a plane surface of area \(A/2\) parallel to the plates and drawn symmetrically between the plates. The displacement current through this area is:
1. \(i\)
2. \(i/2\)
3. \(i/4\)
4. \(i/8\)
The sun delivers \(10^{3}~\text{W/m}^2\) of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimensions \(8\) m\(20\) m will be:
1. \(2.56\times 10^{4}~\text{W}\)
2. \(6.4\times 10^{5}~\text{W}\)
3. \(4.0\times 10^{5}~\text{W}\)
4. \(1.6\times 10^{5}~\text{W}\)
In a region of free space, the electric field at some instant of time is V/m and the magnetic field is . The Poynting vector for these fields is
(1)
(2)
(3)
(4)
A plane electromagnetic wave propagating in the x-direction has wavelength of 60 mm. The electric field is in the y-direction and its maximum magnitude is 33 V/. The equation for the electric field as function of x and t is
(1) 11 sin (t - x/c)
(2) 33 sin (t - x/c)
(3) 33 sin (t - x/c)
(4) 11 sin (t - x/c)
In an electromagnetic wave, if the electric field oscillated sinusoidally with an amplitude of \(48~\text{Vm}^{-1}\), then the RMS value of the oscillating magnetic field will be:
1. \(1.6\times 10^{-8}~\text{T}\)
2. \(1.6\times 10^{-9}~\text{T}\)
3. \(144\times 10^{-8}~\text{T}\)
4. \(11.3\times 10^{-8}~\text{T}\)
The magnetic field in the plane electromagnetic wave is given by
The expression for the electric field will be
(1)
(2)
(3)
(4)