Kinetic Theory — Class 11 Physics NCERT Solutions (Free)

Free step-by-step NCERT solutions for Class 11 Physics chapter "Kinetic Theory" — 8 important questions with detailed answers for CBSE board exam preparation.

TL;DR: Free step-by-step NCERT solutions for Class 11 Physics chapter "Kinetic Theory" — 8 important questions with detailed answers for CBSE board exam prep…

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Key Questions Covered:

  1. Calculate the RMS (root mean square) speed of nitrogen gas molecules at 300 K…
  2. At what temperature will the RMS speed of oxygen molecules be equal to 400 m/…
  3. Calculate the average kinetic energy of a gas molecule at 27°C. Given: Boltzm…
  4. + 5 more questions in the full chapter

Solutions Summary:

Question Status
Calculate the RMS (root mean square) speed of nitrogen ga… ✓ Solved
At what temperature will the RMS speed of oxygen molecule… ✓ Solved
Calculate the average kinetic energy of a gas molecule at… ✓ Solved

Showing 3 of 8 questions

Q1: Calculate the RMS (root mean square) speed of nitrogen gas molecules at 300 K. Given: M = 28 g/mol = 0.028 kg/mol, R = 8.314 J/mol·K.

Step 1: RMS speed formula: v_rms = √(3RT/M) = √(3kT/m) where R = gas constant, T = temperature, M = molar mass Step 2: Substitute values: T = 300 K M = 0.028 kg/mol R = 8.314 J/mol·K v_rms = √(3 × 8.314 × 300 / 0.028) v_rms = √(7482.6 / 0.028) v_rms = √(267,235.7) v_rms = 516.9 m/s ≈ 517 m/s Fina...

Q2: At what temperature will the RMS speed of oxygen molecules be equal to 400 m/s? (M_O₂ = 32 g/mol, R = 8.314 J/mol·K)

Step 1: RMS speed formula: v_rms = √(3RT/M) Step 2: Square both sides: v_rms² = 3RT/M Step 3: Rearrange for T: T = (v_rms² × M)/(3R) Step 4: Substitute values: v_rms = 400 m/s M = 32 g/mol = 0.032 kg/mol R = 8.314 J/mol·K T = (400² × 0.032)/(3 × 8.314) T = (160,000 × 0.032)/(24.942) T = 5120/24....

Q3: Calculate the average kinetic energy of a gas molecule at 27°C. Given: Boltzmann constant k = 1.38 × 10⁻²³ J/K.

Step 1: Average kinetic energy per molecule: KE_avg = (3/2)kT where k = Boltzmann constant, T = absolute temperature Step 2: Convert temperature to Kelvin: T = 27°C = 27 + 273 = 300 K Step 3: Calculate KE_avg: KE_avg = (3/2) × 1.38 × 10⁻²³ × 300 KE_avg = 1.5 × 1.38 × 10⁻²³ × 300 KE_avg = 1.5 × 414...

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