Physics

A diffraction grating reveals the wave property of light by producing an interference pattern due to the wave nature of light. While light is an electromagnetic wave, the key concept demonstrated by a diffraction grating is the wave property (interference and diffraction) of light in general, not specifically emphasizing the electromagnetic aspect. Therefore, the best answer is 'Wave property' as it captures the fundamental phenomenon observed.

Gamma rays (γ-rays) have the highest frequency and thus the highest photon energy among the listed options, making their photons the strongest.

The Davisson-Germer experiment demonstrated electron diffraction, confirming the wave nature of electrons by showing that electrons produce interference patterns when scattered by a crystal lattice.

In Compton scattering, the change in wavelength (Δλ) is given by Δλ = (h/m_ec)(1 - cos θ), where θ is the scattering angle. The maximum change occurs when θ = 180°, as (1 - cos 180°) = 2, the largest possible value.

The time period T of a simple pendulum is proportional to the square root of its length L, i.e., T ∝ √L. If the length becomes four times, the time period becomes √4 = 2 times the original period.

The diameter of a lens is called the aperture, which determines how much light can pass through the lens. The principal axis is an imaginary line through the center of the lens, not its diameter.

The critical angle for glass with a refractive index of about 1.5 (typical for crown glass) when light passes from glass to air (refractive index ~1.0) is calculated using the formula sin(θc) = n2/n1, where n2 is the refractive index of air and n1 is that of glass. This gives sin(θc) = 1/1.5 = 0.6667, so θc = arcsin(0.6667) ≈ 41.8°. Therefore, the critical angle is approximately 42°, making option A the correct answer.

Electrons in atoms do not move in simple classical or vibratory motions; instead, their behavior is best described by standing wave patterns (orbitals) according to quantum mechanics. Hence, 'Standing wave motion' correctly describes the electron's motion in an orbit.

The relativistic mass m is related to the relativistic energy E by the equation m = E/c², where c is the speed of light. This shows that relativistic mass is energy divided by the square of the speed of light.

When a photon reflects off a mirror, its momentum reverses direction. The change in momentum is therefore twice the magnitude of its initial momentum, making it 'double'.