Question
The intensity of a progressing plane wave in loss-free medium is
✓
Answer
(d) $I = 2\pi {n^2}{a^2}\rho v$ ==> $I \propto {n^2}{a^2}v$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
For matter to exist simultaneously in gas and liquid phases
Which of the following figures represent the variation of particle momentum and the associated de-Broglie wavelength?
Column $I$ gives certain situations in which a straight metallic wire of resistance $R$ is used and Column $II$ gives some resulting effects. Match the statements in Column $I$ with the statements in Column $II$ and indicate your answer by darkening appropriate bubbles in the $4 \times 4$ matrix given in the $ORS$.
→| Column $I$ | Column $II$ |
| $(A)$ A charged capacitor is connected to the ends of the wire | $(p)$ A constant current flows through the wire |
| $(B)$ The wire is moved perpendicular to its length with a constant velocity in a uniform magnetic field perpendicular to the plane of motion | $(q)$ Thermal energy is generated in the wire |
| $(C)$ The wire is placed in a constant electric field that has a direction along the length of the wire. | $(r)$ A constant potential difference develops between the ends of the wire |
| $(D)$ A battery of constant emf is connected to the ends of the wire | $(s)$ Charges of constant magnitude appear at the ends of the wire |
Four lamps are connected in the way shown in the figure. When switch $S_2$ is open and switch $S_1$ is on position $-2$ , lamp $-b$ is the brightest, and lamp $-c$ and lamp $-d$ are the dimmest and are of the same brightness. Now $S_2$ is closed and $S_1$ is on position $-1$ , the sequence in brightness of the lamps is (with the first in the sequence being the brightest)
→One end of a long metallic wire of length $L$ is tied to the ceiling. The other end is tied to massless spring of spring constant $K$. A mass $ m$ hangs freely from the free end of the spring. The area of cross-section and Young's modulus of the wire are $A$ and $Y$ respectively. If the mass is slightly pulled down and released, it will oscillate with a time period $T$ equal to
→The major product of the following reaction is
The amplitude of a particle executing $SHM$ about $O$ is $10\, cm.$ Then :
→The graph showing the dependence of intensity of transmitted light on the angle between polariser and analyser is ($I_0$ is intensity of plane polarised light)
→Magnetic fleld changing at the rate of $4\,T/sec$ in a circular region of $5\, cm$ radius. The value of induced electric field at a point $'P'$, which is $10\, cm$ distance away from the centre $'O'$ of region is .....$V/m$
→A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads $49 \,N$, when the lift is stationary. If the lift moves downward with an acceleration of $5\,m/{s^2},$ the reading of the spring balance will be .......... $N$
→