The dual nature of radiation is demonstrated by:

Find the number of photons emitted per second by a $25 \text{ W}$ source of monochromatic light of wavelength $6600 \text{ Å}$. What is the photoelectric current assuming $3 \%$ efficiency for the photoelectric effect?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. $E = hv$	$I$. de Broglie wavelength
$B$. Diffraction and Interference	$II$. Particle nature of light
$C$. $\lambda = h/p$	$III$. Wave nature of light
$D$. Compton effect	$IV$. Energy of photon

Choose the correct answer from the options given below:

An electron moving with speed $v$ and a photon moving with speed $c$ have the same de Broglie wavelength. The ratio of the kinetic energy of the electron to that of the photon is -

Consider the following statements $A$ and $B$ and identify the correct choice in the given answers.
$A$. Tightly bound electrons of target material scatter $X$-ray photon,resulting in the Compton effect.
$B$. Photoelectric effect takes place with free electrons.

One day on a spacecraft corresponds to $2$ days on the earth. The speed of the spacecraft relative to the earth is