Maxwell noted that the speed of the wave solution to the equations of electromagnetism was similar to that measured for light. Disclaimer Feedback, Light, electromagnetism, time, space and relativity, The Australian Office for Learning and Teaching. Which type of electromagnetic radiation travels at the highest speed through a vacuum? The nodes are easiest to see near the bottom, where the incident and reflected amplitudes are most similar in amplitude. c. speed b. The wave equation is applicable here too. b. 18. a a. So here is the experiment. a. half the distance between a crest and a trough The corresponding wavelength of the sound wave at a frequency of 2000Hz is reduced to 10 times smaller than 1.7m. 2c. Thus the nodes in the combined wave do not have an amplitude of zero (except at the point of reflection); rather, they are local minima in the interference pattern. Electromagnetic radiation travels through space without a medium. 11. d a. they are reflected by mirror only How fast is the wave travelling? A crest of a water wave travels 40cm in 5s. 28. b ultraviolet rays. a. These correspond to frequencies as low as 3 Hz and as high as 1 gigahertz (10 9 Hz). 0.25m/s d. 1.1km, 1. b Two video cameras were used. The speed of sound in air in 0.34km.s. A gramophone record was made to play at 45 r.p.m. 12. b. frequency the speed of sound in air remains constant. Calculate the wavelength of this sound wave, 7b.
3.3 The second note is 1.0m a. It receives an echo 1.5s later. Which of the following cannot travel through glass? Frequency of a sound wave is inversely proportional to its wavelength. A vibrator of frequency 3 Hz produces waves with an amplitude of 0.5m and a wavelength of 12cm. b. higher in amplitude and lower in frequency Refer to this for questions 21 to 23. a. blue light b. water ripples c. radio wave d. sound wave. So, in retrospect, we can say that it is perhaps unsurprising that c is the natural relation between space and time. c. 1 m/s Which of the following is an example of longitudinal wave? They are electric and magnetic fields that oscillate at 90° to each other. As the wavelength of the notes are recorded permanently on the record, a reduction in speed reduces the frequency of the notes heard. They can travel through vacuum (do not require any medium to travel). a. The source of any wave is a vibration or oscillation. 990m 14. a. 16. c A large ripple tank with a vibrator working at a frequency of 30 Hz produces 25 complete waves in a distance of 50cm. b. sound 110m How many wavelengths are there in PQ if the length of PQ is 600m? sound in air is close to 340.1 meters per second. 0.75m/s This is an important comparison: Maxwell realised that the waves that are a solution to the equations for electricity and magnetism had a speed similar to that measured for light. e. 10Hz, 19. A boy, using a stopwatch, notes that there is a 3s delay between the flash of lighting and the sound of thunder. Which of the following is not changed when the wave is refracted? Examples of such waves include rope waves and water waves. A wave source of frequency 2000Hz emits waves of wavelength 0.2m. 20. a. its wavelengths are shorter than those of visible light and it is used to treat cancer, b. its frequencies are lower than those of visible light and it is reflected by layers in the upper atmosphere during its transmission, c. its wavelengths are shorter than those of visible light and it is used to detect cracks in lead beams, d. its frequencies are higher than those of visible light and it is absorbed by glass to produce fluorescence, 2a. 14. d 825m At the point of reflection, the incident and reflected waves have the same amplitude, but elsewhere the incident wave has a larger amplitude than the reflected one. Quality control (checking for cracks) in concrete, Medical applications (development of foetus). Amplitude is the maximum displacement from the rest or centre position (high of a crest or depth of a trough). 0.1 m/s What is the velocity with which the waves travel across the surface? Sound is produced by vibrating sources placed in a medium (air). What is the wavelength of the waves broadcast by the station? a. what is the distance from the centre of a compression to the centre of the nearest rarefaction in the wave described in a? 23. d Reverberation occurs when the surface is too close, causing any reflected sound to follow closely behind the direct sound and prolonging the original sound. What frequency do we need to tune our receiver to in order to, Radio waves travel at the speed of light, so in this case v is equal to, 299,792,458 metres per second (m/s). e. 4500m, 17. – The speed of sound is solids like metals are so fast that we can assume/ignore the time it takes to travel a distance. It is usually drawn by joining the wave crests. An observer in the crowd notices that he receives the radio broadcast on his radio 1.6s before he hears the same word from the loudspeakers. 15. b The distance between 2 successive wavefronts is equal to Aluminium is a conductor, so this reflects the electric wave with a phase change of 180°, giving approximately zero electric field in the conductor. Speed of sound differs in different medium, Air: 330 – 340m/s d. speed = 6cm/s; wavelength = 3cm The speed of sound in seawater is 1500m/s. c. radio wave On the ground we have spread aluminium foil. Hence as the cone vibrates, a series of alternate compressions and rarefactions travels outwards from the cone of the loudspeaker which is along the same direction as the vibration of the cone. d. square, 6.