Dual Nature of ...

$${ 10 }^{ -3 }W$$ of 5000 A light is directed on a photoelectric cell. If the current in the cell is 0.16 $$\mu A$$, the percentage of incident photons which produce photo electrons, is 

The energy of a neutron in eV whose de-Broglie wavelength is $$1\mathop {\text{A}}\limits^{\text{0}} $$

If a strong diffraction peak is observed when electron are incident at an angle. 'i' from the normal to the crystal planes with distance 'd' wavelength them (see figure) de Broglie wavelength $$ \lambda_{dB} $$ of electrons can be calculate by the relationship (n is an integer) 

Two large parallel plates are connected with the terminal of $$100V$$ power supply. These plates have a fine hole at the centre. An electron having energy $$200eV$$  is so directed that it passes through the holes. When it comes out it's de-Broglie wavelength is

The figure shows the path of white light's rays which leave in phase from two small source S$$_{1}$$ and S$$_{2}$$ and travel to a point X on a screen .The path difference  is S$$_{2}$$X -- S$$_{1}$$X = 10 $$\times 10^{-7}$$m.What wavelength of light give complete destructive interference at X?

Two particles A and B have de-Broglie's wavelengths $$30 \ \mathring A$$ and $$20 \ \mathring A$$, combined to form a particle C. Momentum is conserved in this process. The possible de-Broglie's wavelength of C is :

The energy that should be added to an electron to reduce its De broglie wavelength from $$10^{-10}$$ m to $$0.5 \times 10^{-10}$$ m will be :

A photocell is illuminated by a small bring source placed $$1 m$$ away. When the same source of light is placed $$1/2\ m$$ away, the number of electrons emitted by photocathode would :

If the de Broglie wavelengths associated with a proton and an $$\alpha$$-particle are equal then the ratio of velocities of the proton and the $$\alpha$$-particle will be:

If the particles listed below all have the same kinetic energy, which one would posses the shortest de-Broglie wavelength.