A capacitor is made of two circular plates each of radius $12~\text{cm}$ and separated by $5.0~\text{cm}.$ The capacitor being charged by an external source. The charging current is constant and equal to $0.15~\text{A}.$ The displacement current across the plates is:
1. $0$
2. $0.14~\text{A}$
3. $0.16~\text{A}$
4. $0.15~\text{A}$

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. $1.01\times 10^{-12}~\text T$

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

The amplitude of the magnetic field part of a harmonic electromagnetic wave in a vacuum is $B_0=510~\text{nT}$. What is the amplitude of the electric field part of the wave?
1. $200~\text{N/C}$
2. $153~\text{N/C}$
3. $150~\text{N/C}$
4. $510~\text{N/C}$

Suppose that the electric field amplitude of an electromagnetic wave is $E_0 = 120~\text{N/C}$ and that its frequency is $\nu = 50.0~\text{MHz}.$ The value of propagation constant $k$ is:
1. $2.01~\text{rad/m}$
2. $1.72~\text{rad/m}$
3. $1.05~\text{rad/m}$
4. $2.41~\text{rad/m}$

In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of $2.0\times 10^{10}~\text{Hz}$ and amplitude $48~\text{V/m}$. What is the amplitude of the oscillating magnetic field?
1. $4.2\times 10^{-8}~\text{T}$
2. $2.4\times 10^{-7}~\text{T}$
3. $3.8\times 10^{-8}~\text{T}$
4. $1.6\times 10^{-7}~\text{T}$

The electric field part of an electromagnetic wave in a vacuum is; $\vec{E}=(3.1~\text{N/C}) \cos \left[(1.8~\text{rad/m}) y+\left(5.4 \times 10^8 ~\text{rad/s}\right)t\right] \hat{i}.$ What is the frequency of the wave?
1. $5.7\times 10^{7}~\text{Hz}$
2. $9.3\times 10^{7}~\text{Hz}$
3. $8.6\times 10^{7}~\text{Hz}$
4. $7.5\times 10^{7}~\text{Hz}$