A progressive wave passes through a medium. It makes a particle of the medium oscillate along line P, while the wave energy moves along line Q. If the wave is transverse, compare the directions of P and Q.
A progressive wave passes through a medium. It makes a particle of the medium oscillate along line P, while the wave energy moves along line Q. If the wave is longitudinal, compare the directions of P and Q.
A tube is sealed at one end. As shown in Fig. 5.1, a loudspeaker is placed close to the other end of the tube. It emits sound of frequency $1.7\,\text{kHz}$. The speed of sound in air inside the tube is $340\,\text{m s}^{-1}$. A stationary wave is formed with an antinode A at the open end of the tube. Only one further antinode A is inside the tube, as shown in Fig. 5.1. Determine the wavelength of the sound.
Determine the tube length $L$.
Determine the maximum wavelength of the sound from the loudspeaker that can form a stationary wave in the tube. State your answer in metres.
Two polarising filters are set with their planes vertical and parallel. The first filter has a transmission axis at $35^{\circ}$ to the vertical, while the second has a transmission axis at angle $\alpha$ to the vertical, as shown in Fig. 5.2. Angle $\alpha$ is greater than $35^{\circ}$ and less than $90^{\circ}$. A beam of vertically polarised light of intensity $8.5\,\text{W m}^{-2}$ is incident normally on the first filter. Show that the intensity of the light transmitted by the first filter is $5.7\,\text{W m}^{-2}$.
The second filter transmits light with intensity $5.2\,\text{W m}^{-2}$. Calculate angle $\alpha$.
Find the maximum wavelength of the sound from the loudspeaker that can form a stationary wave in the tube. Give your answer in metres.