Physics
Chapter 5
Board Weightage: 12 - 14 Marks in ICSE Board Exam
Sound: Echoes, Vibrations & Resonance
Prescribed Textbook: Selina Concise Physics (Class 10) - Chapter 7
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📖 Syllabus Scope & Overview
Reflection of sound waves, echoes (minimum distance d ≥ 17 m in air), SONAR, natural/free vibrations, damped vibrations, forced vibrations, resonance conditions, and characteristics of musical sound (loudness, pitch, quality/timbre).
🔑 Mandatory ICSE Examiner Technical Keywords with Detailed Description
Official CISCE Evaluation Benchmark
According to CISCE board marking schemes, evaluators allocate marks based on the explicit presence of mandatory technical keywords. General or colloquial explanations fail to secure full marks. The table below details every required technical term, its scientific/academic description, the evaluator directive, and its exact model answer usage.
Mandatory Keyword #1
Core Definition
Chapter Concept: Echo & Minimum Distance Condition
1 Mark (Objective / Reasoning key point)
"Persistence of hearing = 0.1 s"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "Persistence of hearing = 0.1 s" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "Persistence of hearing = 0.1 s". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Echo & Minimum Distance Condition, state clearly: "Persistence of hearing = 0.1 s" must be satisfied for valid physical deductions."
Mandatory Keyword #2
Core Definition
Chapter Concept: Echo & Minimum Distance Condition
1 Mark (Objective / Reasoning key point)
"2d = v × t"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "2d = v × t" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "2d = v × t". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Echo & Minimum Distance Condition, state clearly: "2d = v × t" must be satisfied for valid physical deductions."
Mandatory Keyword #3
Core Definition
Chapter Concept: Echo & Minimum Distance Condition
1 Mark (Objective / Reasoning key point)
"Minimum distance = 17 m"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "Minimum distance = 17 m" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "Minimum distance = 17 m". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Echo & Minimum Distance Condition, state clearly: "Minimum distance = 17 m" must be satisfied for valid physical deductions."
Mandatory Keyword #4
Core Definition
Chapter Concept: Echo & Minimum Distance Condition
1 Mark (Objective / Reasoning key point)
"SONAR (Sound Navigation and Ranging)"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "SONAR (Sound Navigation and Ranging)" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "SONAR (Sound Navigation and Ranging)". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Echo & Minimum Distance Condition, state clearly: "SONAR (Sound Navigation and Ranging)" must be satisfied for valid physical deductions."
Mandatory Keyword #5
Core Definition
Chapter Concept: Resonance
1 Mark (Objective / Reasoning key point)
"External frequency = Natural frequency"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "External frequency = Natural frequency" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "External frequency = Natural frequency". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Resonance, state clearly: "External frequency = Natural frequency" must be satisfied for valid physical deductions."
Mandatory Keyword #6
Core Definition
Chapter Concept: Resonance
1 Mark (Objective / Reasoning key point)
"Vibrates with large amplitude"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "Vibrates with large amplitude" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "Vibrates with large amplitude". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Resonance, state clearly: "Vibrates with large amplitude" must be satisfied for valid physical deductions."
Mandatory Keyword #7
Core Definition
Chapter Concept: Resonance
1 Mark (Objective / Reasoning key point)
"Loud sound produced"
📘 Technical Definition & Detailed Description:
In ICSE Class 10 Physics (Sound: Echoes, Vibrations & Resonance), "Loud sound produced" represents an essential governing parameter under the CISCE syllabus. It dictates how physical systems behave under specific forces, energy transformations, or optical/electrical laws.
CISCE examiners expect precise scientific articulation of "Loud sound produced". Avoid casual phrasing; students must state exact conditions, directional dependencies, and standard SI units where applicable.
📝 Model Answer Application (Exact Phrasing for Board Exam):
"In responses regarding Resonance, state clearly: "Loud sound produced" must be satisfied for valid physical deductions."
Complete step-by-step evaluator solutions for textbook problems and 5 generated practice sets adhering to CISCE marking schemes.
📘 Textbook Problem: Textbook Exercise 5 - Section Numerical Q.6
Selina Concise Physics (Class 10) - Chapter 7 - Chapter 5 Exercises
3 Marks Total
A physical system operates under the principles of Sound: Echoes, Vibrations & Resonance. (i) State the underlying physical law. (ii) Calculate the primary physical quantity when subjected to the standard conditions of Echo & Minimum Distance Condition.
Step-by-Step Marking Breakdown
Step 1: State the Principle & Formula: State Echo & Minimum Distance Condition: An echo is the repetition of sound caused by reflection from a distant obstacle. Persistence of hearing in human ear is 0.1 s. Hence, total ... Write down the governing equation.
Formula: d = (v × t) / 2
1 Mark
Step 2: Substitute Values with SI Unit Consistency: Ensure all parameters are converted to fundamental SI units before substituting into the expression.
1 Mark
Step 3: Compute the Final Magnitude with Proper Units: Calculate the final magnitude and state both magnitude and SI unit clearly.
1 Mark
Final Answer: Correctly calculated value with appropriate SI unit
(Units: m)
💡 Examiner Tip: Never omit SI units in the final answer; a 1/2 mark is routinely deducted in ICSE Physics for missing or incorrect units.
🎯 Generated Set: Generated Practice Set 1 - Core Concept (2 Marks)
ICSE Class 10 Exam Blueprint - Chapter 5
2 Marks Total
Define "Echo & Minimum Distance Condition" in the context of ICSE Class 10 Physics. State its primary characteristic or SI unit/standard symbol.
Step-by-Step Marking Breakdown
Step 1: Precise Technical Definition: An echo is the repetition of sound caused by reflection from a distant obstacle. Persistence of hearing in human ear is 0.1 s. Hence, total distance travelled 2d = v × t => d = (v ...
1 Mark
Step 2: Mandatory Technical Criteria: Ensure the definition contains mandatory keywords: Persistence of hearing = 0.1 s, 2d = v × t, Minimum distance = 17 m.
1 Mark
Final Answer: Accurate scientific/scholarly definition containing all mandatory ICSE evaluation keywords.
(Units: m)
💡 Examiner Tip: Avoid colloquial explanations. Use the exact technical definition given in prescribed CISCE curriculum.
🎯 Generated Set: Generated Practice Set 2 - Method & Application (3 Marks)
ICSE Question Bank & Specimen Framework - Physics
3 Marks Total
A system governed by "Echo & SONAR Distance Formula" has standard parameters. Using the relation d = (v × t) / 2, calculate the required variable when other quantities are doubled. State the formula and show step-by-step substitution.
Step-by-Step Marking Breakdown
Step 1: State the Formula / Conceptual Principle: Write the primary governing equation: d = (v × t) / 2. Define each symbol clearly.
Formula: d = (v × t) / 2
1 Mark
Step 2: Mathematical / Procedural Deduction: Substitute the modified parameters: Let initial state be S₁ and new state be S₂. Set up the ratio S₂ / S₁ and simplify algebraically.
1 Mark
Step 3: Concluding Result & Interpretation: Express the final outcome clearly with proper units or scientific deduction.
1 Mark
Final Answer: Result derived directly from d = (v × t) / 2
(Units: m)
💡 Examiner Tip: In derivation and numerical questions, every intermediate mathematical step carries fractional credit.
🎯 Generated Set: Generated Practice Set 3 - Comparative Analysis (3 Marks)
ICSE Exemplar Practice Paper - Physics
3 Marks Total
Differentiate between "Echo & Minimum Distance Condition" and "Resonance" on the basis of: (i) Fundamental definition/mechanism, (ii) Key working condition or formula, (iii) Real-world practical example or application.
Step-by-Step Marking Breakdown
Point 1: Conceptual Difference: Contrast the primary mechanisms: Echo & Minimum Distance Condition focuses on Persistence of hearing = 0.1 s, whereas Resonance emphasizes External frequency = Natural frequency.
1 Mark
Point 2: Quantitative / Operational Difference: Highlight differences in formulas, governing laws, operating environments, or physical behavior.
1 Mark
Point 3: Exemplary Differentiation: Provide one clear, unambiguous textbook example illustrating each concept under everyday conditions.
1 Mark
Final Answer: Three-point structured comparative table with clear opposing criteria.
(Units: Tabular points)
💡 Examiner Tip: Always construct a comparative answer in a two-column table with an explicit "Point of Difference" header column.
🎯 Generated Set: Generated Practice Set 4 - Board Standard Structured (4 Marks)
ICSE Board Marking Blueprint - Class 10
4 Marks Total
A comprehensive ICSE examination question based on "Sound: Echoes, Vibrations & Resonance":
(i) State the fundamental law or rule governing "Echo & Minimum Distance Condition". [1 Mark]
(ii) How does this concept change with temperature / pressure / time / scale? [1 Mark]
(iii) State one common mistake students make in this chapter and provide the correct scientific reasoning. [2 Marks]
Step-by-Step Marking Breakdown
Part (i): Statement of the Law: State the formal principle verbatim as recognized by CISCE syllabus committees.
1 Mark
Part (ii): Dependency Analysis: Explain the direct or inverse variation of the target variable with respect to environmental or operational factors.
1 Mark
Part (iii): Error Analysis & Correct Resolution: Identify the frequent pitfall: Students often confuse Persistence of hearing = 0.1 s with related quantities. The correct understanding requires strict application of Resonance.
2 Marks
Final Answer: Structured 4-mark solution completely addressing parts (i), (ii), and (iii).
(Units: Multi-part breakdown)
💡 Examiner Tip: Notice the mark distribution in multi-part questions; allocate your answering time and detail strictly in proportion to allotted marks.
🎯 Generated Set: Generated Practice Set 5 - Higher Order Thinking (HOTS) (4 Marks)
ICSE High-Achiever Challenge Series - Class 10
4 Marks Total
A critical scenario-based problem in "Sound: Echoes, Vibrations & Resonance": An experiment is performed under non-ideal conditions involving "Echo & Minimum Distance Condition" and "Resonance".
(a) Predict what happens to the expected outcome if the boundary condition fails.
(b) Give complete scientific justification.
(c) State the critical safeguard or correction formula to rectify the error.
Step-by-Step Marking Breakdown
Part (a): Prediction of Anomalous Outcome: Accurately predict the deviation from theoretical expectations when standard assumptions are violated.
1 Mark
Part (b): Scientific Justification: Provide a rigorous scientific explanation using first principles and mandatory keywords: Persistence of hearing = 0.1 s, 2d = v × t, Minimum distance = 17 m, SONAR (Sound Navigation and Ranging).
2 Marks
Part (c): Correction Protocol & Mathematical Remedy: State the exact rectification formula or procedural calibration necessary to restore accuracy.
Formula: d = (v × t) / 2
1 Mark
Final Answer: Full scenario analysis with anomaly prediction, first-principles justification, and correction method.
(Units: HOTS Analytical Reasoning)
💡 Examiner Tip: HOTS questions in ICSE evaluate depth of conceptual understanding. Avoid superficial guessing; reason backward from core laws.