The eye can detect  $5 ×10^4$ photons per square metre per sec of green light ($\lambda$ $= 5000\ \mathop A\limits^o $) while the ear can detect ${10^{ - 13}}\,(W/{m^2})$. The factor by which the eye is more sensitive as a power detector than the ear is close to

The velocity of photon is proportional to (where $v$ is frequency)

Assertion : If the speed of charged particle increases both the mass as well as charge increases.
Reason : If $m_0 =$ rest mass and $m$ be mass at velocity $v$ then $m = \frac{{{m_0}}}{{\sqrt {1 - \frac{{{v^2}}}{{{c^2}}}} }}$ where $c =$ speed of light

A photo sensitive material is at $9\,m$ to the left of the origin and the source of light is at $7\,m $ to the right of the origin along $x$ -axis. The photosensitive material and the source of light start from rest and move, respectively, with $8 \widehat i \, m / s$ and $4 \widehat i \, m / s$ . The ratio of intensities at $t = 0$ to $t = 3\,s$ as received by the photosensitive material is :-

If the momentum of a photon is $p$, then its frequency is

Where $m$ is the rest mass of the photon

Ultraviolet light of wavelength $300 \ nm$ and intensity $1.0 \ watt/m^2$ falls on the surface of a photosensitive material. If $1\%$ of the incident photons produce photoelectrons, then the number of photoelectrons emitted from an area of $1.0\  cm^2$ of the surface is nearly