NEET Waves — Set 9

Question 1

What is the key requirement for a medium to support both transverse and longitudinal waves?

Accepted Answer

A medium must be rigid (have shear modulus) to support transverse waves and compressible (have bulk modulus) for longitudinal waves, properties typical of solids.

Question 2

Which property of a medium allows longitudinal waves to propagate through it but not transverse waves?

Accepted Answer

Longitudinal waves require a medium with bulk modulus (resistance to compression), which fluids possess. Transverse waves need shear modulus (resistance to shearing), which fluids lack due to their inability to sustain shear stress.

Question 3

A wave is described by $ y(x, t) = 0.02 \sin (25x - 75t) $, where $ x $ and $ y $ are in meters and $ t $ in seconds. What is the period of the wave?

Accepted Answer

Compare with $ y = a \sin (kx - \omega t) $, $ \omega = 75 \, \text{rad/s} $. Period: $ T = \frac{2\pi}{\omega} = \frac{2\pi}{75} \approx 0.0838 \, \text{s} $.

NEET Physics: Waves — Practice Set 9

Q1. What is the key requirement for a medium to support both transverse and longitudinal waves?

Q2. Which property of a medium allows longitudinal waves to propagate through it but not transverse waves?

Q3. A wave is described by \( y(x, t) = 0.02 \sin (25x - 75t) \), where \( x \) and \( y \) are in meters and \( t \) in seconds. What is the period of the wave?

Q4. A wave \( y = 0.03 \sin (20x - 40t) \) reflects at an open boundary. What is the equation of the reflected wave?

Q5. A wave on a string has an amplitude of 0.035 m and a frequency of 20 Hz. What is the maximum transverse speed of a particle?

Q6. Two strings produce beats of 3 Hz. One has a frequency of 400 Hz. When the tension in the second string is slightly increased, the beat frequency becomes 2 Hz. What was the original frequency of the second string?

Q7. Two waves of frequencies 496 Hz and 502 Hz interfere. How many beats are heard in 10 seconds?

Q8. A pipe open at both ends has a length of 0.8 m and resonates with a source of frequency 637.5 Hz. What is the harmonic number if the speed of sound is 340 m/s?

Q9. What is the effect on a standing wave’s frequency if the length of the vibrating medium is halved?

Q10. Two waves of frequencies 490 Hz and 495 Hz interfere. How many beats are heard in 8 seconds?