Sound - General Physics - Solved Exam, Exams of Physics

Download Sound - General Physics - Solved Exam and more Exams Physics in PDF only on Docsity! 1 Exam Questions 1. [2011] Describe a simple experiment to show that sound is a form of energy. 2. [2007 OL][2009 OL] A student set up the following experiment to investigate how sound travels through air. An electric bell was placed inside a bell-jar as shown in the diagram. The bell rang and it could be heard clearly. When the pump was switched on it started to pump the air out of the bell- jar and a vacuum was created. At that stage the bell could no longer be heard but it could still be seen ringing. (i) What conclusion could be drawn from this investigation? (ii) When the air was pumped out, the bell could still be seen even though it could not be heard. What difference between light and sound does this show? (iii)During an electric storm lightning is usually seen before thunder is heard. What does this tell us about light and sound? 3. [2007] Describe, using a labelled diagram in the box, an investigation you could carry out to show that sound requires a medium in which to travel. 4. [2007][2008 OL][2010][2012 OL] The picture shows a flash of lightning. (i) Which is detected first, the flash of lightning or the clap of thunder? (ii) What does this tell us about the speed of light? 5. [2010 OL] Copy the sentences below into your copy and complete them using words from the list on the right. (i) Sound is a form of _____________________. (ii) A reflected sound is called an ___________________. (iii)Sound is produced by ______________. 6. [2006] [2009] How are echoes produced? 7. [2009 OL] (i) The soldier in the diagram has safety goggles on his hat. Give one reason why safety goggles should be used in the laboratory. (ii) The sign on the right is found displayed at shooting ranges and in many factories. What instruction does this sign give? (iii)Why is it important to obey the instruction given by this sign? Energy Electricity Noise Echo Vibrations 2 Exam Solutions 1. Use a speaker which is emitting sound Suspend a table tennis ball by a thread in front of the speaker. Result: the table tennis ball moves. 2. (i) Sound will not travel through a vacuum / sound needs a medium to travel. (ii) Light can travel through a vacuum / light doesn’t need a medium. (iii)Light travels faster than sound 3. Set up the apparatus as shown with the bell ringing. Turn on the vacuum pump; as the air gets pumped out the sound gradually fades 4. (i) Flash of lightning (ii) Light travels faster than sound 5. (i) Energy (ii) Echo (iii)Vibrations 6. Echoes are produced when sound reflects off a surface. 7. (i) Eye protection (ii) Ear protection must be worn to protect your ears. (iii)To prevent damage to hearing Other Test Questions 1. How is sound produced? 2. Draw a labelled diagram of an apparatus used to show that sound is a form of energy. 3. Why is the moon sometimes referred to as “the silent planet”? 4. Draw a diagram and write a brief note to demonstrate that sound is caused by vibrations. 5. What is ultrasound? 6. What is the speed of sound in air? 7. Give two differences between sound and light waves. 8. Give two applications of reflected sound. 9. If the time-lag between seeing lightning and hearing thunder is 5 seconds, how far away is the storm? 10. When a girl was a certain distance from a high cliff she shouted loudly. One and a half seconds later the echo returned from the cliff. How far was the girl from the cliff? (take the speed of sound to be 340 m/s). 11. A guitar string is plucked. The sound is heard. It seems simple, but there are a few stages in between. Can you put the following stages in the correct order? vibrating eardrum, brain, vibrating source, vibrating air, nerve Make sure to check out Audacity