Numerical Problems 8.1: The wavelength of the signals from a radio transmitter is 1500 m and the frequency is 200 Khz. What is the wavelength for a transmitter operating at 1000 Khz and with what speed the radio waves travel. (Ans: 300 m, 3 ｘ10⁸ m s⁻¹)

(click Here for Solution)


Numerical Problems 8.2: Two speakers are arranged as shown in figure 8.24. The distance between them is 3 m and they emit a constant tome of 344 Hz. A microphone P is moved along a line parallel to and 4.00 m from the line connecting the two speakers. It is found that tone of maximum loudness is heard and displayed on the CRO when microphone is on the center of the line and directly opposite each speakers. Calculate the speed of sound. (Ans: 344 m s⁻¹)

(click Here for Solution)


Numerical Problems 8.3: A stationary wave is established in a string, which is 120 cm long and fixed at both ends. The string vibrates in four segments, at a frequency of 120 Hz. Determine its wavelength and the fundamental frequency. (Ans: 6.6ｘ10⁻⁹ rad)

(click Here for Solution)


Numerical Problems 8.4: The frequency of the note emitted by a stretched string is 300 Hz. What is the frequency of this note when: 

(a) Length of the wave is reduced by one third without changing tension.

(b) The tension is increased by one-third without changing the length of the wire. 

(Ans: 450 Hz, 346 Hz)

(click Here for Solution)


Numerical Problems 8.5: An organ pipe has a length of 50 cm. Find the frequency of its fundamental note and the next harmonic when it is: 

(a) Open at both ends. 

(b) Closed at one end (speed of sound = 350 m s⁻¹). 

(Ans: (a) 350 Hz, 700 Hz, (b) 175 Hz, 525 Hz)

(click Here for Solution)


Numerical Problems 8.6: A church organ consists of pipes, each open at one end, of different lengths. The minimum length is 30 mm and the longest is 4 m. Calculate the frequency range of fundamental notes. (speed of sound = 340 m s⁻¹). (Ans: 21 Hz to 2833 Hz)

(click Here for Solution)


Numerical Problems 8.7: Two tuning forks exhibit beats at a beat frequency of 3 Hz. The frequency of one fork is 256 Hz. Its frequency is then lowered slightly by adding a bit of wax to one of its prong. The two forks then exhibit a beat frequency of 1 Hz. Determine the frequency of second tuning fork.

(click Here for Solution)


Numerical Problems 8.8: Two cars P and Q are traveling along a motorway in the same direction. The leading car P travels at a steady speed of 12 m s⁻¹, the other car Q, traveling at a steady speed of 20 m s⁻¹, sound its horn to emit a steady note which P's driver estimates has a frequency of 830 Hz. What frequency does Q's own driver hear? (Speed of sound = 340 m s⁻¹) (Ans: 810 Hz)

(click Here for Solution)


Numerical Problems 8.9: A train sounds its horn before it sets off from the station and an observer waiting on the platform estimates its frequency at 1200 Hz. The trains then moves off and accelerates steadily. Fifty seconds after departure, the driver sounds the horn again and the platform observer estimates the frequency of 1140 Hz. Calculate the train speed 50 s after departure. How far from the station is the train after 50 s? (Speed of sound = 340 m s⁻¹). (Ans: 17.9 m s⁻¹, 448 m)


************************************

Shortcut Links For 


1. Website for School and College Level Physics   
2. Website for School and College Level Mathematics  
3. Website for Single National Curriculum Pakistan - All Subjects Notes 

© 2022-Onwards by Academic Skills and Knowledge (ASK)     

Note:  Write me in the comment box below for any query and also Share this information with your class-fellows and friends.