To produce an instantaneous displacement current of \(2~\text{mA}\) in the space between the parallel plates of a capacitor of capacitance \(4~\mu\text{F}\), the rate of change of applied variable potential difference \(\left(\dfrac{dV}{dt}\right) \) must be:
1. \( 800~ \text{V} / \text{s} \)
2. \( 500~ \text{V} / \text{s} \)
3. \( 200~ \text{V} / \text{s} \)
4. \( 400 ~\text{V} / \text{s}\)

Subtopic:  Displacement Current |
 80%
Level 1: 80%+
NEET - 2023
Hints

\(\varepsilon_0\) and \(\mu_0\) are the electric permittivity and magnetic permeability of free space respectively. If the corresponding quantities of a medium are \(2\varepsilon_0\) and \(1.5\mu_0\) respectively, the refractive index of the medium will nearly be:
1. \(\sqrt2\)
2. \(\sqrt3\)
3. \(3\)
4. \(2\)
Subtopic:  Properties of EM Waves |
 82%
Level 1: 80%+
NEET - 2023
Hints

An electromagnetic wave of frequency \(\nu=3.0\) MHz passes from a vacuum into a dielectric medium with relative permittivity \(\varepsilon =4.0.\) Then:
1. wavelength is doubled and frequency becomes half
2. wavelength is halved and frequency remains unchanged
3. wavelength and frequency both remain unchanged
4. wavelength is doubled and frequency unchanged
Subtopic:  Properties of EM Waves |
 73%
Level 2: 60%+
NEET - 2013
Hints

advertisementadvertisement

The speed of electromagnetic waves is:
1. higher in vacuum compared to other media.
2. lower in vacuum compared to other media.
3. independent of the medium.
4. lower in some media than in vacuum, and higher in others.
Subtopic:  Properties of EM Waves |
 68%
Level 2: 60%+
Hints

When light propagates through a material medium of relative permittivity, \(\varepsilon_{r}\) and relative permeability, \(\mu_{r}\) the velocity of light, \(v\) is given by: (\(c\) = velocity of light in vacuum)
1. \(v=\dfrac{{c}}{\sqrt{\varepsilon_{r} \mu_{{r}}}}\) 2. \(v={c}\)
3. \(v=\sqrt{\dfrac{\mu_{{r}}}{\varepsilon_{{r}}}}\) 4. \(v=\sqrt{\dfrac{\varepsilon_{{r}}}{\mu_{{r}}}}\)
Subtopic:  Properties of EM Waves |
 87%
Level 1: 80%+
NEET - 2022
Hints

Match List I with List II.
List - I
(Electromagnetic waves)
List - II
(Wavelength)
(a) AM radio waves (i) \(10^{-10}~\text{m}\)
(b) Microwaves (ii) \(10^{2} ~\text{m}\)
(c) Infrared radiation (iii) \(10^{-2} ~\text{m}\)
(d) \(X\)-rays (iv) \(10^{-4} ~\text{m}\)

Choose the correct answer from the options given below:
(a) (b) (c) (d)
1. (ii) (iii) (iv) (i)
2. (iv) (iii) (ii) (i)
3. (iii) (ii) (i) (iv)
4. (iii) (iv) (ii) (i)
Subtopic:  Electromagnetic Spectrum |
 74%
Level 2: 60%+
NEET - 2022
Hints

advertisementadvertisement

When an electromagnetic wave of frequency \(f_0\) undergoes refraction at the interface of two transparent (non-absorbing) media, the frequency of the transmitted wave is \(f_t.\) Then:
1. \(f_t=f_0\)
2. \(f_t>f_0\)
3. \(f_t<f_0\)
4. \(f_t\neq f_0\)
Subtopic:  Properties of EM Waves |
 77%
Level 2: 60%+
Hints

The region on the left of the \(y\)-axis \((x<0)\) represents vacuum, and the region on the right \((x>0)\) represents a transparent medium. An electromagnetic wave travelling along the \(x\)-axis given by:   
\(\vec E_1(x,t)=E_1\hat j~\sin(\omega t-k_0x),\) where \(x<0,\)

is incident on to the medium on the right. The transmitted wave in the medium is:   
\(\vec E_2(x,t)=E_2\hat j~\sin(\omega t-2k_0x),\) where \(x>0.\)

The refractive index of the medium is:
1. \(2\) 2. \(\sqrt2\)
3. \(4\) 4. \(2\sqrt2\)
Subtopic:  Properties of EM Waves |
 67%
Level 2: 60%+
Hints

A plane electromagnetic waveform given by:    \(\vec {E}_1=E_0\hat j\sin(\omega t-kx)\)
propagates along the \(x\)-axis. A second waveform given by:    \(\vec {E}_2=E_0\hat k\sin(\omega t-kx)\)
is also allowed to propagate. The magnetic field has the amplitude: (Assume speed of light in vacuum is \(c\))
 
1. \(\dfrac{E_0}{c}\) 2. \(\dfrac{E_0}{2c}\)
3. \(\dfrac{\sqrt2E_0}{c}\) 4. Zero
Subtopic:  Properties of EM Waves |
 65%
Level 2: 60%+
Hints

advertisementadvertisement

Which of the following situation(s), can cause the radiation of an electromagnetic wave?
(A) a varying sinusoidal current flowing through a capacitor
(B) an electric dipole, whose size (and magnitude) is oscillating with time
(C) a steady current flowing through a toroid

Choose the correct option from the given ones:
1. only (A)
2. only (B)
3. only (A) & (B)
4. (A), (B), (C)
Subtopic:  Generation of EM Waves |
 67%
Level 2: 60%+
Hints