Extra Explaining Questions - WAVES

WAVES

1. Lucy is playing in her paddling pool. As she pushes a ball up and down in the water it makes a small wave as shown in a figure below.
   
   


1. Which way does the water move as waves move across the pool?
   [Show answer]

   The water itself moves up and down only, not across the pool.
   It simply vibrates vertically while the wave travels outward from the point where Lucy is pushing the ball.


2. Describe the motion of the other balls in the pool
   [Show answer]

   The other balls will bob up and down as the waves pass under them.
   

   • They stay almost in the same place, just rising and falling due to the wave motion.


2. Explain why guitars have strings of varying thickness.
   [Show answer]

   Guitars have strings of varying thickness to produce different frequencies.
   
   The guitar uses strings of different thickness so each string can produce a different pitch even when stretched to similar lengths.


3. Explain why radio waves are similar to light waves but not sound waves?
   [Show answer]

   1. Both radio waves and light waves are electromagnetic waves
   • They do not require a medium to travel.
   • They can move through vacuum (empty space).
   2. Both travel at the same speed in vacuum
   Radio waves and light waves both travel at 3 × 10⁸ m/s (The speed of light).
   
   
   3. Both are transverse waves
   Their vibrations are perpendicular to the direction of travel.


4. Explain why a duck a duck rmains floating at the same place as a wave passes by the water in a lake?
   [Show answer]

   Water waves are transverse wave therefore a duck experiences only the vertical displacement and not horizontal displacement
5. Briefly explain one reason why the walls and floors of broadcasting studio and a theatre room are always covered with soft curtains and carpets.
   [Show answer]

   To reduce echoes and unwanted reflections of sound
   Soft materials like curtains and carpets absorb sound waves preventing echoes, reverberations, and noise, allowing clearer and quality sound during broadcasting or performances.


6. Briefly explain why we can hear people talking in the near places even without seeing them.
   [Show answer]

   Sound travels through air and can diffract around obstacles, allowing us to hear people who are nearby even if we cannot see them.


7. Briefly explain why an electric bell ringing inside a closed bottle does not produce sound.
   [Show answer]

   Sound needs a medium (air, liquid, or solid) to travel.
   When air is removed from the bottle, a vacuum is formed. In a vacuum, there are no particles to carry sound waves.
   Therefore, sound cannot travel to the outside, and you hear nothing.


8. Explain the following phenomena as applied in physics field.
   1. A bat can fly in the dark during the night without hitting an obstacle.
      [Show answer]

      The bat produces high-frequency sound waves (ultrasonic sounds). When the waves strike an obstacle (like a wall, tree, or insect), they produce an echo. The bat interprets the returning echoes and determine how far away an object, its size and shape e.t.c
   
   
   2. Why it is not advisable for soldiers to March across a bridge in rhythm.
      [Show answer]

      If the frequency of the soldiers marching steps matches the natural frequency of the bridge, resonance can occur.
      This causes the bridge to vibrate with very large amplitudes, which can lead to structural damage or even collapse.
   
   
9. A piano wire and a turning fork produce different notes at the same time and beats are heard. What could be done on the piano wire in order to emit a note of the same frequency as vibrating fork. (Give three points)
   [Show answer]

   1. By changing the length of the wire
   2. By changing the thickness (diameter) of the wire
   3. By changing the tension on the wire

   
   HINT
   A question needs the Factors Affecting the Frequency of a Stretched String