If an electromagnetic wave propagating through vacuum is described by \(E_y= E_0 \sin(kx-\omega t); ~B_z= B_0\sin(kx-\omega t),\) then:
1. \(E_0k=B_0\omega\)
2. \(E_0B_0 = \omega k\)
3. \(E_0\omega= B_0k\)
4. \(E_0B_0= \frac{\omega}{k}\)

Which of the following is not an electromagnetic wave?

1. Radio wave

2. Micro wave

3. Cosmic rays

4. $\mathrm{\gamma }$-rays

About \(5\)% of the power of a \(100\) W light bulb is converted to visible radiation. What is the average intensity of visible radiation at a distance of \(1\) m from the bulb?

1. \(0.472\) W/m²
2. \(0.398\) W/m²
3. \(0.323\) W/m²
4. \(0.401\) W/m²

A radio can tune in to any station in the \(7.5\) MHz to \(12\) MHz bands. What is the corresponding wavelength band?
1. \(40\) to \(25\) m
2. \(10\) to \(100\) m
3. \(50\) to \(60\) m
4. \(20\) to \(10\) m

A parallel plate capacitor is made of circular plates each of radius \(R=6.0~\text{cm}\) has a capacitance \(C=100~\text{pF}.\) The capacitor is connected to a \(230~\text V\) AC supply with an (angular) frequency of \(300~\text{rad/s}.\) The amplitude of \(\vec{B}\) at the point \(3~\text{cm}\) from the axis between the plate is:
          
1. \(1.12\times 10^{-11}~\text T\)
2. \(2.01\times 10^{-12}~\text T\)
3. \(1.63\times 10^{-11}~\text T\)
4. \(1.01\times 10^{-12}~\text T\)

Consider an oscillator which has a charged particle oscillating about its mean position with a frequency of \(300\) MHz. The wavelength of electromagnetic waves produced by this oscillator would be:
1. \(1\) m
2. \(10\) m
3. \(100\) m
4. \(1000\) m

Light with an average flux of \(20~\text{W/cm}^2\) falls on a non-reflecting surface at normal incidence having a surface area \(20~\text{cm}^2\). The energy received by the surface during time span of \(1\) minute is:
1. \(12\times 10^{3}~\text{J}\)
2. \(24\times 10^{3}~\text{J}\)
3. \(48\times 10^{3}~\text{J}\)
4. \(10\times 10^{3}~\text{J}\)

The magnetic field in a plane electromagnetic wave is given by:
\(B_y = 2\times10^{-7} ~\text{sin}\left(\pi \times10^{3}x+3\pi\times10^{11}t\right )\text{T}\)${}_{}$
The wavelength is:
1. \(\pi\times 10^{3}~\text{m}\)
2. \(2\times10^{-3}~\text{m}\)
3. \(2\times10^{3}~\text{m}\)
4. \(\pi\times 10^{-3}~\text{m}\)