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                | 31. | The particles in the wave separated through __________ multiple of  ? are out of phase to each other |  
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				| A. | (n) | B. | (n+1) |  
				 				 | C. | (n+1/2) | D. | both (a) and (c) |  
                        
                        
                            Answer: Option C Explanation:    |  
 
            
            
                | 32. | Waves produced at the surface of water by a pencil executing vibrating motion if held vertically at a frequency of 50Hz are |  
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				| A. | Longitudinal | B. | Transverse |  
				 				 | C. | Periodic | D. | both (a) and (c) |  
                        
                        
                            Answer: Option D Explanation:    |  
 
            
            
                | 33. | Newton estimated the speed of sound |  
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				| A. | 281m/sec | B. | 333m/sec |  
				 				 | C. | 340m/sec | D. | all of the above |  
                        
                        
                            Answer: Option A  Explanation:    |  
 
            
            
                | 34. | Laplace found that the alternate compressions and rarefactions produced in sound waves follows |  
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				| A. | isothermal law | B. | adiabatic law |  
				 				 | C. | isochoric law | D. | all of the above |  
                        
                        
                            Answer: Option B Explanation:    |  
 
            
            
                | 35. | For destructive interference of sound waves the path difference between two interfering sounds should be |  
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				| A. | n? | B. | (n+1/2)? |  
				 				 | C. | some time n? and some times (n+1/2)? | D. | none of these |  
                        
                        
                            Answer: Option B Explanation:    |  
 
            
            
                | 36. | The speed of sound in hydrogen is __________ time than that in oxygen |  
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				| A. | Two times | B. | Three times |  
				 				 | C. | Four time | D. | Six time |  
                        
                        
                            Answer: Option C Explanation:    |  
 
            
            
                | 37. | The beats frequency (sensible) for a human car is |  
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                            Answer: Option B Explanation:    |  
 
            
            
                | 38. | The speed of stationary waves in a stretched string are independent of |  
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				| A. | Number of loops | B. | Tension in the string |  
				 				 | C. | Point where string is plucked | D. | both (a) and (c) |  
                        
                        
                            Answer: Option D Explanation:    |  
 
            
            
                | 39. | Fundamental frequency of stationary waves in open pipe is ________ times the frequency in closed pipe. |  
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				| A. | One | B. | Two |  
				 				 | C. | Four time | D. | None of these |  
                        
                        
                            Answer: Option B Explanation:    |  
 
            
            
                | 40. | Which phenomena can be applied to estimate the velocity of star with respect to earth |  
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				| A. | Dopplers effect | B. | Interference of waves |  
				 				 | C. | Beats phenomena | D. | All of these |  
                        
                        
                            Answer: Option A  Explanation:    |  
 
 
			
			
 
 
 
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