Two particles have identical charges. If they are accelerated through identical potential differences, then the ratio of their deBroglie wavelength would be

The number of photons $(\lambda =6630 \mathrm{\AA })$ that strike per second on a totally reflecting screen (as shown in figure), so that a force of $1 \mathrm{N}$ is exerted on the screen, is approximately.

An impulse laser may be treated as a source of photons that are emitted during the time interval of the pulse which is followed by a time interval when no photons are produced. Pulses are periodically repeated. A laser beam of diameter $d=10$ microns is directed upward and is perpendicular to the thin foil surface which has an index of reflection $\rho =0.50$ (see the sketch of the experiment). The index of reflection of the surface is the ratio of the reflected energy to the impact energy. A pulse with duration of $0.13 \mathrm{ms}$ has a total energy of $10 \mathrm{J}$. What is the mass of the piece of foil that can be supported in the air solely by the light pressure of the laser beam?

Arrange the following electromagnetic radiations per quantum in the order of increasing energy

$A:$ Blue light

$B:$ Yellow light

$C:$ $X$-ray

$D:$ Radiowave