Speed of Travelling Wave NEET Questions

Physics - Oscillations and Waves

Speed of Travelling Wave MCQ Questions


13.
In the formula v = √(T/Îŧ) for wave speed on a string, the tension T plays the role of:
A.
The linear mass density equivalent
B.
The inertial property — larger tension resists wave propagation
C.
The energy stored per unit length
D.
The elastic restoring property — larger tension means stronger restoring force when string is displaced, allowing faster propagation
😑 View Answer Rough Work Error
ANSWER :
D. The elastic restoring property — larger tension means stronger restoring force when string is displaced, allowing faster propagation
14.
Two strings, A and B, are made of the same material and have the same length and cross-section. String A is under tension T_A and String B is under tension T_B = 4T_A. The ratio of wave speeds v_A : v_B is:
A.
2 : 1
B.
1 : 4
C.
1 : 2 (since both strings have the same Îŧ, and v ∝ √T)
D.
4 : 1
😑 View Answer Rough Work Error
ANSWER :
C. 1 : 2 (since both strings have the same Îŧ, and v ∝ √T)
15.
The general formula for the speed of longitudinal waves in a medium with bulk modulus B and density Ī is derived using dimensional analysis. The result is:
A.
v = √(BĪ)
B.
v = √(Ī/B)
C.
v = √(B/Ī), where B provides the elastic restoring property and Ī provides the inertial property
D.
v = B/Ī
😑 View Answer Rough Work Error
ANSWER :
C. v = √(B/Ī), where B provides the elastic restoring property and Ī provides the inertial property
16.
For a longitudinal wave in a solid bar with Young's modulus Y and density Ī, the wave speed is v = √(Y/Ī). This formula applies when:
A.
The bar is thin so lateral expansion is negligible — only longitudinal (axial) stress and strain are relevant, making Y the appropriate modulus
B.
The frequency is very high (ultrasonic range only)
C.
The material has zero Poisson's ratio
D.
The bar is very thick (wider than it is long)
😑 View Answer Rough Work Error
ANSWER :
A. The bar is thin so lateral expansion is negligible — only longitudinal (axial) stress and strain are relevant, making Y the appropriate modulus
17.
The speed of longitudinal sound waves in a fluid with bulk modulus B and density Ī is v = √(B/Ī). Why is the speed of sound generally HIGHER in liquids than in gases?
A.
Liquids have lower bulk modulus than gases
B.
Liquids have MUCH higher bulk modulus B than gases (liquids are far harder to compress); the increase in B more than compensates for the higher density Ī
C.
Liquids have lower density than gases
D.
The formula v = √(B/Ī) does not apply to liquids
😑 View Answer Rough Work Error
ANSWER :
B. Liquids have MUCH higher bulk modulus B than gases (liquids are far harder to compress); the increase in B more than compensates for the higher density Ī
18.
Speed of sound in steel is approximately 5941 m/s, while in air it is about 343 m/s. The ratio v_steel/v_air ≈ 17.3. This large ratio primarily arises because:
A.
Steel's bulk modulus B is enormously larger than air's (by a factor of ~10âļ), while its density is only ~6000 times higher — the ratio B/Ī is much larger for steel
B.
Air has higher bulk modulus than steel
C.
Steel has lower density than air
D.
Steel supports transverse waves which travel faster than longitudinal waves in air
😑 View Answer Rough Work Error
ANSWER :
A. Steel's bulk modulus B is enormously larger than air's (by a factor of ~10âļ), while its density is only ~6000 times higher — the ratio B/Ī is much larger for steel