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The photoelectric effect demonstrates that light A Is purely a wave B Has particle-like properties (photons) C Is longitudinal D Cannot transfer energy Explanation Photons carry discrete energy quanta E=hνE=h\nuE=hν. In the photoelectric effect, increasing the intensity (at fixed frequency above cutoff) primarily increases A Stopping potential B Number of emitted electrons (photoelectron current) C…

Polarization of light proves that light is A Longitudinal wave B Transverse wave C Scalar wave D Sound-like wave Explanation Only transverse waves can be polarized. Unpolarized light has its electric field A In a fixed plane B Randomly oriented in all directions perpendicular to propagation C Parallel to propagation D Circular only Malus’ law…

Diffraction of light is more pronounced when A Aperture ≫ wavelength B Aperture ≈ wavelength C Aperture = infinity D Light is incoherent Explanation Diffraction becomes significant when aperture size is comparable to λ. Fraunhofer diffraction refers to A Diffraction with source and screen at finite distances B Diffraction with source at infinity and screen…

Interference of light occurs due to A Reflection only B Refraction only C Superposition of coherent waves D Diffraction only Explanation Interference = superposition of two coherent waves with stable phase difference. For interference, sources must be A Intense B Widely separated C Phase-locked (coherent) D Monochromatic only In YDSE, fringe width β is given…

The law of reflection states that the angle of incidence equals the angle of A Refraction B Reflection C Deviation D Diffraction Explanation By definition: θ₁ = θr measured from the normal. Snell’s law relates refractive indices as A n₁sinθ₁ = n₂sinθ₂ B n₁/n₂ = sinθ₁/sinθ₂ C n₁sinθ₂ = n₂sinθ₁ D n₁cosθ₁ = n₂cosθ₂ Explanation…

Magnetic force on a current element Idl in a magnetic field is A Idl⋅B B Idl×B C B/I D Zero Explanation Lorentz force for current element. Magnetic dipole moment of a current loop is A IA B NIA C μ₀IA D IB Explanation For N turns, m = NIA. Field at the axial point of…

The force between two parallel currents is A Always repulsive B Always attractive C Attractive if currents are in same direction D Attractive only if currents differ Magnetic field intensity inside a long solenoid is independent of A Number of turns B Current C Length D Radius A current loop behaves like A An electric…

A current element produces a magnetic field whose magnitude is given by A Ampere’s law B Biot–Savart law C Faraday’s law D Maxwell–Ampere law Explanation Biot–Savart law determines magnetic field from current elements. Magnetic field inside a long solenoid is A Zero B Non-uniform C Nearly uniform D Inversely proportional to current Magnetic field in…

The magnetic field at a distance r from a long straight current-carrying wire varies as A 1/r² B r C 1/r D Constant Explanation Biot–Savart law gives B=μ0I2πrB = \frac{\mu_0 I}{2\pi r}B=2πrμ0​I​, so B∝1/rB \propto 1/rB∝1/r. The direction of magnetic field produced by a current-carrying conductor is given by A Fleming’s left-hand rule B Maxwell’s…

In electrostatics, the curl of electric field equals A charge density B magnetic flux C zero D potential Explanation Electrostatic fields are conservative. The electric field between large parallel plates (ignoring edges) is A zero B uniform C proportional to r D inversely proportional to r² Explanation Plate geometry creates uniform field. In Poisson’s equation,…