COMEDK 2023 Morning Shift | Electromagnetic Waves Question 2 | Physics

A plane electromagnetic wave of frequency $$20 \mathrm{~MHz}$$ travels through a space along $$x$$-direction. If the electric field vector at a certain point in space is $$6 \mathrm{~Vm}^{-1}$$, then what is the magnetic field vector at that point?

$$2 \times 10^{-8} \mathrm{~T}$$

$$\frac{1}{2} \times 10^{-8} \mathrm{~T}$$

$$2 \mathrm{~T}$$

$$\frac{1}{2} \mathrm{~T}$$

COMEDK 2023 Evening Shift

MCQ (Single Correct Answer)

-0

What feature of the infrared waves make it useful for the haze photography?

Since it is invisible

Since it has large wave length

Since it is absorbed by the medium

Since it has high frequency

COMEDK 2022

MCQ (Single Correct Answer)

-0

Speed of electromagnetic wave in a medium having relative permittivity $$\varepsilon_r$$ and relative permeability $$\mu_r$$ is (speed of light in air, $$c=3\times10^8$$ m/s)

$${1 \over {\sqrt {{\mu _r}{\varepsilon _r}} }}$$

$${c \over {\sqrt {{\mu _r}{\varepsilon _r}} }}$$

$$c\sqrt {{{{\mu _r}} \over {{\varepsilon _r}}}} $$

$${c \over {{\mu _r}{\varepsilon _r}}}$$

COMEDK 2022

MCQ (Single Correct Answer)

-0

A 30 mW laser beam has a cross-sectional area of 15 mm². The magnitude of the maximum electric field in this electromagnetic wave is given by

[Permuittivity of space, $$\varepsilon_0=9\times10^{-12}$$

Speed of light, $$c=3\times10^8$$ m/s]

1.22 kV/m

12 kV/m

10 kV/m

201 kV/m

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