1
COMEDK 2023 Morning Shift
+1
-0

The ratio of amplitude of magnetic field to the amplitude of electric field of an electromagnetic wave propagating in vacuum is

A
reciprocal of speed of light in vacuum
B
the speed of light in vacuum
C
proportional to frequency of the electromagnetic wave
D
inversely proportional to the frequency of the electromagnetic wave
2
COMEDK 2023 Morning Shift
+1
-0

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?

A
$$2 \times 10^{-8} \mathrm{~T}$$
B
$$\frac{1}{2} \times 10^{-8} \mathrm{~T}$$
C
$$2 \mathrm{~T}$$
D
$$\frac{1}{2} \mathrm{~T}$$
3
COMEDK 2023 Evening Shift
+1
-0

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

A
Since it is invisible
B
Since it has large wave length
C
Since it is absorbed by the medium
D
Since it has high frequency
4
COMEDK 2022
+1
-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)

A
$${1 \over {\sqrt {{\mu _r}{\varepsilon _r}} }}$$
B
$${c \over {\sqrt {{\mu _r}{\varepsilon _r}} }}$$
C
$$c\sqrt {{{{\mu _r}} \over {{\varepsilon _r}}}}$$
D
$${c \over {{\mu _r}{\varepsilon _r}}}$$
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