Worksheets › Class 12 › Wave Optics
Class 12 Wave Optics worksheet
CBSE Physics. Young's double slit, fringe width, single-slit diffraction, Malus's law, Brewster angle. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
In Young's double-slit experiment, λ = 430 nm, the slits are 1.5 mm apart and the screen is 2 m away. The fringe width is:
- 0.0573 mm
- 5.73 mm
- 1.15 mm
- 0.573 mm
Answer
(d) 0.573 mm
β = λD/d
- 2.
In a double-slit experiment the fringe width is 1.3 mm. The 5th dark fringe is at a distance from the central bright fringe of:
- 6.5 mm
- 7.8 mm
- 5.85 mm
- 13 mm
Answer
(c) 5.85 mm
y = (n − ½)β
- 3.
The Brewster angle for light going from air into a medium of refractive index 1.5 is:
- tan⁻¹(4/3)
- tan⁻¹(1.6)
- 60°
- tan⁻¹(1.5)
Answer
(d) tan⁻¹(1.5)
tan i_B = n
Section B · short answer
- 4.
In Young's experiment λ = 520 nm, d = 1.5 mm and D = 3 m. Find the fringe width and the distance of the 5th bright fringe from the centre.
Answer
1.04 mm; 5.2 mm
β = λD/d; y = nβ
- 5.
A double-slit set-up gives fringes 2.68 mm wide in air. What is the fringe width when the whole apparatus is put in a liquid of refractive index 5/4?
Answer
2.144 mm
λ falls to λ/n, and so does β
Section C · long answer
- 6.
A double-slit experiment uses light containing wavelengths 400 nm and 600 nm, with d = 2 mm and D = 3 m. Find the fringe width for each, and the least distance from the centre at which bright fringes of both wavelengths coincide.
Answer
0.6 mm and 0.9 mm; 1.8 mm (the 3rd bright fringe of 400 nm meets the 2nd of 600 nm)
n₁ × 400 = n₂ × 600
Fresh sheets for your child
In the app, every Wave Optics sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.