Single Choice

The electric field in an electromagnetic wave is given by $$E=(100N/C)\sin\omega \left(t-\dfrac{x}{c}\right)$$ If the energy contained in a cylinder of cross-section $$10cm^3$$ and length $$50$$ cm along the x-axis is $$4.4\times 10^{-8} J/m^3$$, then the intensity of the wave is?

A$$12.4 W/m^2$$
B$$13.2 W/m^2$$
Correct Answer
C$$15.7 W/m^2$$
D$$11.9 W/m^2$$

Solution

SIMILAR QUESTIONS

Electromagnetic Waves

The mean intensity of radiation on the surface of the Sun is about $$10^8 \,W/m^2$$. The rms value of the corresponding magnetic field is closest to:

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Electromagnetic Waves

A point isotropic sound source is located in the perpendicular to the plane of a ring drawn through the centre $$O$$ of the ring. The distance between the point $$O$$ and the source is $$l=1.00\ m$$ the radius of the ring is $$R=0.50\ m.$$ Find the mean energy flow across the area enclosed by the ring if at the point $$O$$ the intensity of sound is equal to $$I_{0}=30\mu\ W/m^{2}.$$ The damping of the waves is negligible.

Electromagnetic Waves

The distance from the source at which the sound is not heard.

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The oscillation amplitude of particles of the medium; compare it with the wavelength of sound.

Electromagnetic Waves

A laser emits at 424 nm in a single pulse that lasts $$0.500 \mu s$$. The power of the pulse is 2.80MW. If we assume that the atoms contributing to the pulse underwent stimulated emission only once during the $$0.500 \mu s$$.how many atoms contributed?

Electromagnetic Waves

A light detector (your eye) has an area of $$2.00 \times 10^{-6} \mathrm{m}^{2}$$ and absorbs $$80 \%$$ of the incident light, which is at wavelength $$500 \mathrm{nm}$$. The detector faces an isotropic source, $$3.00 \mathrm{m}$$ from the source. If the detector absorbs photons at the rate of exactly $$4.000 \mathrm{s}^{-1},$$ at what power does the emitter emit light?

Electromagnetic Waves

In Figure, an isotropic point source of light S is positioned at distance d from a viewing screen A and the light intensity $$I_P$$ at point P (level with S) is measured. Then a plane mirror M is placed behind S at distance d. By how much is $$I_P$$ multiplied by the presence of the mirror?

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