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When a plane electromagnetic wave travels in vaccum, the average electric energy density is given by ($E_o$ is the amplitude of the electric field)
In a plane electromagnetic wave , the electric field oscillates sinusoidaly at a frequency of $ 2.0 \times 10^10 Hz$. if the peak value of electric field is $60 Vm^{-1}$ the average energy density (in$ Jm^{-3}$) of the magnetic field of the wave will be (given $ \mu o = 4 \pi \times 10^{-7} T m/A $)
The average energy density of the magnetic field in an electromagnetic wave can be calculated using the formula: $$ u_B = rac{1}{2} rac{E_0^2}{c^2 imes rac{1}{ ext{μ}_0}} $$ Given that the peak electric field $E_0 = 60 ext{Vm}^{-1}$, $c = 3 imes 10^8 ext{ms}^{-1}$, and $ ext{μ}_0 = 4 ext{π} imes 10^{-7} ext{Tm/A}$, we find that: $$ u_B = rac{1}{2} rac{(60)^2}{(3 imes 10^8)^2 imes 4 ext{π} imes 10^{-7}} ext{Jm}^{-3}$$ Simplifying, we get: $$ u_B = rac{1}{2 ext{π}} imes 10^{-7} ext{Jm}^{-3} $$
Which of the following pairs of the component of space and time varying $ \vec E = ( E_x \hat i + Ey \hat j + Ez \hat k ) $ and $ \vec B = ( B_x \hat i + B y \hat j + Bz \vec k ) $ would generate a plane electromagnetic wave travelling in +ve y direction
Infrared radiations are detected by
Infrared radiations are detected by bolometers. A bolometer is a device that measures the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance.
Electromagnetic wave is produced by oscillating electric and magnetic fields $ \vec E $ and $ \vec B $ . Choose only the incorrect statement from the following
In an electromagnetic wave, the electric field ($\vec{E}$) and magnetic field ($\vec{B}$) are always perpendicular to each other and also perpendicular to the direction of propagation of the wave. Thus, the statement '$\vec{E}$ is parallel to $\vec{B}$' is incorrect.
The potential difference between the plates of a parallel plate capacitor is charging at the rate of $ 10^{6} Vs^{-1} $ . If the capatance is $ 2 \mu F $ . The displacement current in the dielectric of the capacitor will be
Which of the following electromagnetic wave has the least frequency?
Among the given options, radiowaves have the least frequency. The electromagnetic spectrum is ordered by increasing frequency as follows: radiowaves < microwaves < infrared radiation < x-rays.
Which of the following electromagnetic wave has the least wavelength?
Electromagnetic waves have varying wavelengths, from long radio waves to very short gamma rays. Among the given options, ultraviolet rays have the shortest wavelength. Radio waves have the longest wavelength, followed by microwaves, visible waves, and then ultraviolet rays. Hence, ultraviolet rays have the least wavelength.
Which of the following waves are not transverse in nature ?
Transverse waves are waves in which the movement of the medium is perpendicular to the direction of the wave. Electromagnetic waves, such as light, x-rays, and microwaves, are transverse waves. Sound waves in air are longitudinal waves, where the movement of the medium is in the same direction as the wave. Therefore, sound waves traveling in air are not transverse in nature.
An electromagnetic wave
Electromagnetic waves are not deflected by electric or magnetic fields because they consist of oscillating electric and magnetic fields that propagate through space. The fields are self-perpetuating and do not require a medium, hence they are not influenced by external electric or magnetic fields. Therefore, the correct option is 'none of these'.
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The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.