IB DP Physics Mock Exam HL Paper 2 Set 3 - 2025 Syllabus
IB DP Physics Mock Exam HL Paper 2 Set 3
Prepare for the IB DP Physics Mock Exam HL Paper 2 Set 3 with our comprehensive mock exam set 3. 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
Question
Two loudspeakers A and B are initially equidistant from a microphone M. The frequency and
intensity emitted by A and B are the same. A and B emit sound in phase. A is fixed in position.
B is moved slowly away from M along the line MP. The graph shows the variation with
distance travelled by B of the received intensity at M.
(a) Explain why the received intensity varies between maximum and minimum values. [3]
(b) State and explain the wavelength of the sound measured at M. [2]
(c) B is placed at the first minimum. The frequency is then changed until the received
intensity is again at a maximum.
Show that the lowest frequency at which the intensity maximum can occur is about 3kHz.
Speed of sound = 340ms-1 [2]
Answer/Explanation
Ans.
(a) movement of $B$ means that path distance is different « between $B M$ and $A M$ » OR
movement of B creates a path difference «between $B M$ and $A M » \checkmark$
interference
OR
superposition «of waves» $\checkmark$
maximum when waves arrive in phase $/$ path difference $=\mathrm{n} \times$ lambda
OR
minimum when waves arrive « $180^{\circ}$ or $\pi$ ” out of phase / path difference $=(n+1 / 2)$ x lambda $\checkmark$
(b) wavelength $=26 \mathrm{~cm} \checkmark$
peak to peak distance is the path difference which is one wavelength
$O R$
this is the distance B moves to be back in phase “with $A » \checkmark$
(c)
$
\ll \frac{\lambda}{2} n=13 \mathrm{~cm}
$
$
f=« \frac{c}{\lambda}=\frac{340}{0.13}=» 2.6 « \mathrm{kHz} » \checkmark
$