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With what velocity should an observer approach stationary sound source, so that the apparent frequency of sound should appear double the actual frequency? (v is the velocity of sound)

1) v/2 2) 3v 3) 2v 4) v Answer: 4) v Solution: Given, f’ = 2f f’ = f[(v + v0)/(v... View Article

1) 640 ms-1 2) 340 ms-1 3) 170 ms-1 4) 85 ms-1 Answer: 3) 170 ms-1 Solution: Original frequency = f0... View Article

1) 36 kg–wt 2) 27 kg–wt 3) 18 kg–wt 4) 72 kg–wt Answer: 1) 36 kg–wt Solution: n1 = k√T1 n2... View Article

1) 5 Hz 2) 15 Hz 3) 10 Hz 4) 2 Hz Answer: 1) 5 Hz Solution: 5λ/2=L ⇒5λ/2=10 m Therefore,... View Article

1) 100/101 2) 99/100 3) 1 4) 2 Answer: 3) 1 Solution: f = (1/2l)√(T/μ) Take log and differentiate, we get... View Article

1) 200 s-1 2) 100 s-1 3) 300 s-1 4) 250 s-1 5) 150 s-1 Answer: 1) 200 s-1 Solution: Frequency... View Article

1) 2 2) 3 3) 1 4) 5 5) 4 Answer: 2) 3 Solution: λ = v/f = 330/500 = 0.66... View Article

1) 5 Hz 2) 10 Hz 3) 20 Hz 4) 15 Hz Answer: 3) 20 Hz Solution: Distance between two nodes... View Article

1) 1 : 1 2) 2 : 1 3) 1 : 4 4) 1 : 2 Answer: 4) 1 : 2... View Article

1) 25f 2) 5f 3) 10f 4) f Answer: 2) 5f Solution: The fundamental frequency f=(1/2L)√(T/m) Therefore, (f′/f)=√(T′/T) √(25T/T) =5 or... View Article

1) 2 : 1 2) 1 : 2 3) 1 : 1 4) 1 : 4 Answer:3) 1 : 1... View Article

1) 330 ms-1 2) 660 ms-1 3) 990 ms-1 4) 115 ms-1 5) 550 ms-1 Answer: 2) 660 ms-1 Solution: For... View Article

a) 0.08o b) 0.16o c) 0.20o d) 0.32o Answer: b) 0.16o Solution: Δx = dsinθ = λ/2 sinθ = λ/2d θ = sin-1(λ/2d)... View Article

a) reflected light b) refracted light c) both d) neither Answer: a) reflected light Solution: When the light is incident at... View Article

a) it reduces the light intensity to half on account of polarization b) it is fashionable c) it has good... View Article

a) tan-1 (3/2) b) tan-12 c) tan-1 (3/4) d) tan-1 (4/3) Answer: a) tan-1 (3/2) Solution: When angle between reflected and refracted... View Article

a) 312.5 × 10-3 cm b) 31.25 × 10-3 cm c) 312 cm d) 312.5 × 10-3 mm Answer: a) 312.5... View Article

a) 10 angle b) 1’ angle c) 1 mm d) 1 cm Answer: b) 1’ angle Solution: The resolution of the... View Article

a) Bands will disappear b) Bands will become narrow c) Bands will get spaced apart d) Bands will remain unchanged.... View Article

(a) 120 (b) 720 (c) 400 (d) None of these Solution: Total number of letters = 7 Number of vowels... View Article