The principle of superposition IB DP Physics Study Notes - 2025 Syllabus
The principle of superposition IB DP Physics Study Notes
The principle of superposition IB DP Physics Study Notes at IITian Academy focus on specific topic and type of questions asked in actual exam. Study Notes focus on IB Physics syllabus with Students should understand
superposition of waves and wave pulses
Standard level and higher level: 5 hours
Additional higher level: 6 hours
- IB DP Physics 2025 SL- IB Style Practice Questions with Answer-Topic Wise-Paper 1
- IB DP Physics 2025 HL- IB Style Practice Questions with Answer-Topic Wise-Paper 1
- IB DP Physics 2025 SL- IB Style Practice Questions with Answer-Topic Wise-Paper 2
- IB DP Physics 2025 HL- IB Style Practice Questions with Answer-Topic Wise-Paper 2
Superposition – constructive interference
∙Wave superposition is simply the addition of two or more waves passing simultaneously through a medium.
∙Superposition is also called interference and can be constructive or destructive, or anything in between.
∙Consider two in-phase pulses coming from each end of a taut rope.
∙The amplitudes x0 of the two pulses add together, producing a momentary pulse of amplitude 2x0.
Superposition – destructive interference
∙Wave superposition is simply the addition of two or more waves passing simultaneously through a medium.
∙Superposition is also called interference and can be constructive or destructive, or anything in between.
∙Consider two 180° out-of-phase pulses coming from each end of a taut rope.
∙The amplitudes x0 of the two pulses cancel, producing a momentary pulse of amplitude 0.
Example:
Two pulses travel toward each other from opposite ends of a taut rope. Each pulse has amplitude \( x_0 = 2.5 \, \text{cm} \). Analyze what happens when:
a) The pulses are in phase (crest meets crest)
b) The pulses are 180° out of phase (crest meets trough)
▶️ Answer/Explanation
a) Constructive Interference:
The two waves are in phase, so their amplitudes add.
Resultant amplitude = \( x = x_0 + x_0 = 2.5 + 2.5 = \boxed{5.0 \, \text{cm}} \)
A larger pulse momentarily forms at the point of overlap.
b) Destructive Interference:
The two waves are 180° out of phase (crest and trough), so their amplitudes cancel.
Resultant amplitude = \( x = x_0 – x_0 = 0 \)
The rope appears flat for an instant at the point of overlap.
IB Physics The principle of superposition Exam Style Worked Out Questions
Question
Monochromatic light of wavelength λ is incident on two slits S1 and S2. An interference pattern is observed on the screen.
O is equidistant from S1 and S2. A bright fringe is observed at O and a dark fringe at X.
There are two dark fringes between O and X. What is the path difference between the light arriving at X from the two slits?
A. \(\frac{\lambda}{2}\)
B. \(\frac{3\lambda}{2}\)
C. \(\frac{5\lambda}{2}\)
D. \(\frac{7\lambda}{2}\)
Answer/Explanation
Answer – C
Dark fringe n = 3
Between O and X two dark fringe are there and X is also dark Fringe , so n =3
Question
An interference pattern with minima of zero intensity is observed between light waves. What must be true about the frequency and amplitude of the light waves?
Answer/Explanation
Ans : C
Interference in a phenomenon in which two waves of equal amplitude are superimposed to create a resulting wave of greater or lesser amplitude. Interference typically refers to the interaction of waves that are associated or compatible with each other, either because they come from the same source or because they have the same(or nearly the same) frequency.