IB DP Physics Mock Exam HL Paper 2 Set 1 - 2025 Syllabus
IB DP Physics Mock Exam HL Paper 1B Set 1
Prepare for the IB DP Physics Mock Exam HL Paper 2 Set 1 with our comprehensive mock exam set 1. Test your knowledge and understanding of key concepts with challenging questions covering all essential topics. Identify areas for improvement and boost your confidence for the real exam
▶️ Answer/Explanation
(a)
(i) The detected frequency (\(1600\,Hz\)) is lower than the emitted frequency (\(1700\,Hz\)), indicating that the detector is moving away from the loudspeaker.
(ii) Using the Doppler equation for a moving observer, \[ f’ = f\left(\frac{v – u_o}{v}\right) \] \[ 1600 = 1700\left(\frac{340 – u_o}{340}\right) \] \[ u_o = 20\,m\,s^{-1}. \]
(b)
(i) The wavelength in air is \[ \lambda = \frac{v}{f} = \frac{340}{1700} = 0.20\,m. \] (ii) The reflected path length is \(LP + PD = 0.50 + 0.50 = 1.00\,m\), while the direct path length is \(0.70\,m\). The path difference is therefore \(0.30\,m\). Since \(\frac{0.30}{0.20} = 1.5\lambda\), the waves arrive at D out of phase, resulting in destructive interference.
(c)
At point P, the angle of incidence is approximately \(44^\circ\). Sound travels much faster in water than in air. Applying Snell’s law shows that refraction would require \(\sin\theta_r > 1\), which is not possible. Therefore, the sound undergoes total internal reflection and cannot enter the water.