JEE Physics - MCQ Practice Questions
Physics is where JEE ranks are usually won or lost, since a single conceptual slip changes the whole answer. Questions here span mechanics, rotational motion, thermodynamics, waves and oscillations, electrostatics, current electricity, magnetism, optics, and modern physics. Numerical problems carry full derivations so you can see which step you skipped, not just which option was right.
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In Fraunhofer diffraction by a single slit, if the slit width is doubled, how does the angular width of the central maximum change?
Two slits of widths w₁ and w₂ produce a diffraction pattern with intensity ratio I₁:I₂ = 4:1. What is the ratio of their widths?
A biconvex lens (n = 1.5) has both radii of curvature equal to 20 cm. What is its focal length?
In a double-slit experiment, if one slit is covered with a transparent film of thickness t and refractive index n, the central bright fringe shifts. What is the path difference introduced?
A monochromatic light source of wavelength λ is incident on a diffraction grating with 500 lines/mm. The second-order maximum is at 30°. What is the wavelength?
A parallel beam of light undergoes diffraction through a circular aperture of diameter D. The radius of the first dark ring in Fraunhofer diffraction is proportional to:
In Fraunhofer diffraction through a circular aperture, the angular radius of the first dark ring (Airy disk) is θ = 1.22λ/D. For D = 1 mm and λ = 500 nm, what is this angle in radians?
In a compound microscope, the objective has focal length 0.5 cm and eyepiece has focal length 5 cm. If the least distance of distinct vision is 25 cm, the magnifying power is:
In a fiber optics cable, light undergoes total internal reflection. The minimum refractive index of the core material needed to guide light from air is:
When light passes through a glass slab of thickness t and refractive index n, the lateral displacement is maximum when the angle of incidence is:
In Brewster's angle incidence, the reflected and refracted rays are:
A thin air gap of thickness d is created between two glass plates. For constructive interference in reflected light with wavelength λ, the condition is:
In a diffraction grating with 5000 lines/cm, the second order spectrum is observed at angle 30°. The wavelength of light is:
In a compound microscope, the objective has focal length 0.5 cm and eyepiece has focal length 5 cm. The distance between them is 20 cm. The magnifying power is approximately:
A concave mirror forms a real image 4 times larger than the object. The object is placed at distance u from the mirror. The focal length is:
In a Newton's rings experiment, dark fringe appears when the air gap thickness is:
In photoelectric effect, the stopping potential V₀ for a metal is 2V. If the frequency of incident light is doubled, the new stopping potential will be:
A 1 gram sample of a radioactive isotope with atomic mass 100 undergoes decay. Initial activity is 10¹⁵ Bq. The decay constant is approximately:
An electron and a proton have the same kinetic energy. The ratio of their de Broglie wavelengths (λₑ/λₚ) is:
A nucleus of mass number A and atomic number Z emits an alpha particle. The recoil kinetic energy of the daughter nucleus is 0.5 MeV. What is the kinetic energy of the alpha particle? (Assume non-relativistic motion)