IB PHYSICS HL(Higher level) – 2024 – Practice Questions- All Topics
Topic 4.4 Wave behavior
Topic 4 Weightage : 5 %
All Questions for Topic 4.4 – Reflection and refraction , Snell’s law, critical angle and total internal reflection , Diffraction through a single-slit and around objects , Interference patterns , Double-slit interference , Path difference
Question
Monochromatic light of wavelength λ is incident on a double slit. The resulting interference pattern is observed on a screen a distance y from the slits. The distance between consecutive fringes in the pattern is 55 mm when the slit separation is a. λ, y and a are all doubled. What is the new distance between consecutive fringes?
A 55 mm
B 110 mm
C 220 mm
D 440 mm
▶️Answer/Explanation
Ans: B
Fringe width is given by
\(\beta =\frac{\lambda \times y}{a}\)
if \(\lambda\) , y and a are doubled
\({\beta }’ =\frac{2\lambda \times2y}{2a}=2 \times \frac{\lambda \times y}{a}=2\times 55=110 \; mm\)
Question
Light is incident from air on the surface of a transparent medium.
When V is equal to the Brewster angle, which angle is equal to 90°?
A. \({\text{V}} + {\text{W}}\)
B. W only
C. \({\text{X}} + {\text{Y}}\)
D. Z only
▶️Answer/Explanation
Markscheme
C
Ref: https://www.iitianacademy.com/ib-dp-physics-topic-4-waves-4-4-wave-behavior-study-notes/
POLARIZATION BY REFLECTION (BREWSTER’S LAW)
Now V = W Since Angle of incident = Angle of reflection ( Law of reflection)
Hence
\(W+Z= 90\)
Now \(W+X+Y+Z =180^0\) ( Angle of Straight line)
Hence \( X+Y= 180 -90 =90^0\)
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