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Complete Mechanical Waves objective questions from basic to toughest JEE Advanced level.

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🌊 WAVES (Mechanical Waves)

Objective Questions – Page 9 (Extreme Level)

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Q81️⃣ (Wave + SHM Link)

In a transverse wave, the maximum speed of a particle is:

• A) ωA
• B) kA
• C) ω²A
• D) k²A

Answer: A

Key: Particle motion = SHM ⇒ vmax = ωA

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Q82️⃣ (Standing Wave – Energy)

In a standing wave, average kinetic energy of particles at nodes is:

• A) Maximum
• B) Minimum
• C) Zero
• D) Constant

Answer: C

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Q83️⃣ (String – Tension Change)

If tension in a stretched string is increased four times, wave speed becomes:

• A) 2v
• B) 4v
• C) v/2
• D) v/4

Answer: A

Logic: v ∝ √T

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Q84️⃣ (Sound – Echo)

Minimum distance to hear a distinct echo in air at 20°C is:

• A) 8.5 m
• B) 10 m
• C) 17 m
• D) 34 m

Answer: C

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Q85️⃣ (Beats – Formula)

If two tuning forks produce 6 beats per second and one has frequency 256 Hz, the other frequency could be:

• A) 250 Hz
• B) 262 Hz
• C) 256 Hz
• D) 260 Hz

Answer: B

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Q86️⃣ (Closed Pipe – Fundamental)

Fundamental frequency of a closed pipe of length L is:

• A) v/2L
• B) v/L
• C) v/4L
• D) 2v/L

Answer: C

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Q87️⃣ (Doppler – Observer Moving)

Observer moves away from stationary source with speed u. Observed frequency:

• A) Increases
• B) Decreases
• C) Same
• D) Zero

Answer: B

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Q88️⃣ (Wave Equation – Identification)

Which equation represents a stationary wave?

• A) y = A sin(kx − ωt)
• B) y = A cos(kx + ωt)
• C) y = 2A sin kx cos ωt
• D) y = A sin ωt

Answer: C

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Q89️⃣ (Intensity Level – Decibel)

If intensity becomes 100 times, sound level increases by:

• A) 10 dB
• B) 20 dB
• C) 100 dB
• D) 2 dB

Answer: B

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Q90️⃣ (Concept – Reflection)

Phase change on reflection from a rigid boundary is:

• A) 0
• B) π/2
• C) π
• D) 2π

Answer: C

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✅ Objective Page 9 Completed
Difficulty: 🔥🔥🔥🔥🔥 (JEE Advanced)

👉 Type Objective Page 10 to finish Objective Series