Jawaharlal Nehru Technological University Hyderabad
Jawaharlal Nehru Technological University Hyderabad B.Tech I Year Engineering Physics-I Previous Question Paper (September - 2023 - R16)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
PART A
A parallel beam of light (λ = 5900 Å) is incident on a thin glass plate (μ = 1.55) such that the angle of refraction into the plate is 30°. Find the smallest thickness of the glass plate which will appear bright by reflection.
Answer
For a thin film, the condition for constructive interference (brightness) in reflected light is 2μt cos(r) = (n + 1/2)λ. For the smallest thickness, we take n = 0, giving 2μt cos(r) = λ/2. Given λ = 5900 Å, μ = 1.55, and r = 30°, we have t = λ / (4μ cos 30°). Substituting the values: t = 5900 / (4 * 1.55 * 0.866) = 5900 / 5.369 = 1098.9 Å.
Explain the diffraction due to N- slits.
Answer
Diffraction due to N-slits (diffraction grating) involves the interference of light waves emerging from multiple parallel slits. The resultant intensity is given by I = I_0 [sin²(β)/β²] * [sin²(Nα)/sin²(α)], where the first term represents the single-slit diffraction pattern and the second term represents the interference pattern of N slits. As N increases, the principal maxima become sharper and more intense, while secondary maxima decrease in intensity, leading to high-resolution spectral separation.
What is a quarter wave plate?
Answer
Sign in to view the complete answer paper.
What are the applications of lasers?
Answer
Sign in to view the complete answer paper.
Explain the construction of a fiber.
Answer
Sign in to view the complete answer paper.
What are the characteristics of a graded index fiber?
Answer
Sign in to view the complete answer paper.
Show the lattice parameters in a cubic orthorhombic unit cell.
Answer
Sign in to view the complete answer paper.
Calculate the packing factor for Diamond lattices.
Answer
Sign in to view the complete answer paper.
What is Schottky defect?
Answer
Sign in to view the complete answer paper.
X-rays of wavelength 1.5 Å are diffracted by a sample in second order at an angle of 45°. Calculate the inter planar spacing.
Answer
Sign in to view the complete answer paper.
PART B
Explain the theory of interference in thin films by reflected light.
Answer
Sign in to view the complete answer paper.
What is a grating? Describe the grating experiment to determine the wavelength of a color.
Answer
Sign in to view the complete answer paper.
Describe Newton’s rings experiment to determine the wave length of a light Source.
Answer
Sign in to view the complete answer paper.
Describe Fraunhofer diffraction due to single slit quantitatively.
Answer
Sign in to view the complete answer paper.
Explain the phenomenon of double refraction with diagram.
Answer
Sign in to view the complete answer paper.
Describe the construction and working of Ruby laser.
Answer
Sign in to view the complete answer paper.
Describe the construction and working of Nicol’s prism.
Answer
Sign in to view the complete answer paper.
Distinguish between spontaneous and stimulated emission.
Answer
Sign in to view the complete answer paper.
What are the characteristics of step index fiber?
Answer
Sign in to view the complete answer paper.
Explain principle of optical fiber.
Answer
Sign in to view the complete answer paper.
Explain the reasons for power loses in fibers.
Answer
Sign in to view the complete answer paper.
Derive the expressions for Numerical aperture and Acceptance angle in fibers.
Answer
Sign in to view the complete answer paper.
Calculate the atomic radius and coordination number in SC, BCC and FCC Lattices.
Answer
Sign in to view the complete answer paper.
Describe the seven crystal systems with diagrams.
Answer
Sign in to view the complete answer paper.
Describe the Bravais lattices in crystallography.
Answer
Sign in to view the complete answer paper.
Calculate the atomic radius and coordination number in HCP and Diamond.
Answer
Sign in to view the complete answer paper.
What are point defects? Classify them with neat diagrams.
Answer
Sign in to view the complete answer paper.
What is Burger’s vector? Explain the nature of tilt and twin defects in crystals.
Answer
Sign in to view the complete answer paper.
Describe the powder method to determine the crystal structure.
Answer
Sign in to view the complete answer paper.
What are line defects? Classify them with neat diagrams.
Answer
Sign in to view the complete answer paper.