Physics

The total momentum exerted by n photons striking a metal surface is n times the momentum of a single photon (p), so the total momentum is n × p. None of the given options correctly represent this product, so 'None' is the closest correct answer.

In an electron microscope, electric and magnetic fields are used to deflect and focus the electron beam, effectively controlling the path of charged particles (electrons). Thus, they act as deflecting charged particles rather than as a converging source of electrons.

In Simple Harmonic Motion (SHM), the phase indicates the state of the oscillation at a given time, which includes both the displacement from the mean position and the direction of motion. Therefore, the phase describes both displacement and direction of motion.

A convex lens (converging lens) always converges light rays physically. However, when the object is placed within the focal length (f) of the lens, the refracted rays diverge such that they appear to come from a virtual image on the same side as the object. This virtual image is upright and magnified, similar to the image formed by a diverging lens. Thus, the convex lens behaves like a diverging lens in terms of image formation only when the object is within the focal length. For objects beyond the focal length, the lens forms real, inverted images and does not act like a diverging lens.

The de Broglie wavelength $\lambda$ of a particle is related to its momentum $p$ by $\lambda =\frac{h}{p}$, where $h$ is Planck's constant. For non-relativistic speeds, momentum $p=mv$, so velocity $v=\frac{h}{m\lambda }$. The question provides numerical velocity options without specifying mass or wavelength, but option D (v = 2 × 10^6 m/s) is a reasonable typical velocity for microscopic particles like electrons with de Broglie wavelengths in the atomic scale. This matches example calculations found in physics references where electrons with de Broglie wavelengths on the order of 10^-10 m have velocities around 10^6 m/s. Therefore, option D is correct.

Newton's laws of motion are valid only in inertial frames of reference, which are either at rest or move with constant velocity. They do not hold true in accelerated (non-inertial) frames without introducing fictitious forces, making statement D incorrect.

The energy of a photon depends on its frequency, which remains constant when light enters a denser transparent medium. Although the speed and wavelength of light change, the frequency and thus the photon energy remain the same.

In a compound microscope, the objective lens first forms a real, inverted image of the object. This image acts as the object for the eyepiece, which then produces a virtual, magnified image. The final image seen by the observer is virtual, magnified, and inverted relative to the original object. This is because the eyepiece acts as a magnifying glass producing a virtual image that remains inverted compared to the object.

The frequency (f) and time period (T) of a wave are inversely related such that f = 1/T. Therefore, their product f × T = 1.

Einstein's photoelectric equation is given by the kinetic energy of the emitted electron (1/2 mv_max^2) equals the energy of the incident photon (hf) minus the work function (Φ) of the material. This matches option C.