Tiêu đề 15.Waves(Mobile).pdf ✅

BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 15 WAVES #QID# 5295 (1.) Intensity level of sound of intensity I is 30 . dB The ratio 0 I I is (Where 0 I is the threshold of hearing) (a.) 3000 (b.) 1000 (c.) 300 (d.) 30 ANSWER: b 3 10 0 0 10log 30 10   = =  =     I I L I I #QID# 5296 (2.) An organ pipe, open from both end produces 5 beats per second when vibrated with a source of frequency 200 . Hz The second harmonic of the same pipes produces 10 beats per second with a source of frequency 420 . Hz The frequency of source is (a.) 195 Hz (b.) 205 Hz (c.) 190 Hz (d.) 210 Hz ANSWER: b EXPLANATION: (b) Initially number of beats per second = 5

BUY COURSE FROM STORE TO GET INSTANT ANSWER AND EXPLANATION OF EACH QUESTION SPARK PCMB | DOWNLOAD APP NOW| +91-920-630-6398 Path difference 1 4 2 2 2         =   =   = m Hence v n m s = =  =  120 4 480 / #QID# 5299 (5.) A tuning fork of frequency 500 Cycles/s is sounded on a resonance tube. The first and second resonance is obtained at 17 cm and 52 cm. the velocity of sound in −1 ms is (a.) 175 (b.) 350 (c.) 525 (d.) 700 ANSWER: b EXPLANATION: (b) If the frequency of fork v, then speed of sound is given by v v l l = − 2 ( 2 1 ) Where 1 l and 2 l are length of air columns. Given, v=500 cycles/s, 2 2 52 52 10 − l cm m = =  2 1 17 17 10 − l cm m = = ( ) 2 2 500 52 17 10−  =  −  v 1 350  = − v ms #QID# 5300 (6.) The equation of a transverse wave is given by y x t = − 10sin 0.01 2  ( ) Where x and y are in cm and t is in second. Its frequency is (a.) 1 10 sec− (b.) 1 2 sec− (c.) 1 1 sec− (d.) 1 0.01 sec−