A police car with a siren of frequency $8\, kHz$ is moving with uniform velocity $36\, km/hr$ towards a tall building which reflects the sound waves. The speed of sound in air is $320 \,m/s$. The frequency of the siren heard by the car driver is
- 8.50 kHz
- 9.50 kHz
- 7.75 kHz
- 7.50 kHz
The Correct Option is A
Solution and Explanation
Apparent frequency of sound heard by car driver (observer) reflected from the building will be
$f'=f\bigg(\frac{v+v_0}{v-v_s}\bigg)=8\bigg(\frac{320+10}{320-10}\bigg)=8.5\, kHz$
$\therefore$ Correct option is (a).
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The relativistic effect in Global Navigation Satellite System satellites has two parts, of which the first part is the time dilation due to the shift in the fundamental frequency of the satellite clock. The second part is due to the satellite’s semi-major axis and __________
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\[ \begin{array}{|c|l|c|l|} \hline \textbf{Column I} & \textbf{SAR Sensor} & \textbf{Column II} & \textbf{Frequency Band} \\ \hline P & \text{NOVASAR} & 1 & \text{X-BAND} \\ Q & \text{RISAT-1} & 2 & \text{C-BAND} \\ R & \text{TERRASAR} & 3 & \text{L-BAND} \\ S & \text{ALOS PALSAR} & 4 & \text{S-BAND} \\ \hline \end{array} \] The variations of kinetic energy \( K \), potential energy \( U \), and total energy \( E \) as a function of displacement of a particle in SHM is shown in the figure. The value of \( x_3 \) is
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Concepts Used:
Waves
Waves are a disturbance through which the energy travels from one point to another. Most acquainted are surface waves that tour on the water, but sound, mild, and the movement of subatomic particles all exhibit wavelike properties. inside the most effective waves, the disturbance oscillates periodically (see periodic movement) with a set frequency and wavelength.
Types of Waves:
Transverse Waves -
Waves in which the medium moves at right angles to the direction of the wave.
Examples of transverse waves:
- Water waves (ripples of gravity waves, not sound through water)
- Light waves
- S-wave earthquake waves
- Stringed instruments
- Torsion wave
The high point of a transverse wave is a crest. The low part is a trough.
Longitudinal Wave -
A longitudinal wave has the movement of the particles in the medium in the same dimension as the direction of movement of the wave.
Examples of longitudinal waves:
- Sound waves
- P-type earthquake waves
- Compression wave