The ratio of momenta of an electron and α-particle which are accelerated from rest by a
potential difference of 100 V is :

In the given nuclear reaction A, B, C, D, E represents

Starting with a sample of pure \[Cu^{66}\], (7/8) of it decays into Zn in 15 minutes. The corresponding half-life is

The threshold frequency for a photosensitive metal is \[3.3\times 10^{14} Hz\]. If light of frequency \[8.2\times 10^{14} Hz\] is incident on this metal, the cut-off voltage for the photoelectric emission is nearly :

Surface area of \[Al^{27}\] is S0, then surface area of \[Zn^{64}\] is :

A star initially has \[10^{40}\] deuterons. It produces energy via the processes ;

If the average power radiated by the star is \[10^{16}\] W, the deuteron supply of the star is
exhausted in a time of the order of :

When a point source of monochromatic light is at a distance of 0.2 m from a photoelectric cell, the cut-off voltage and the saturation current are 0.6 volt and 18 mA respectively. If the same source is placed 0.6 m away from the photoelectric cell, then :

The figure shows different graphs between stopping potential (V0) and frequency (n) for photosensitive surface of caesium, potassium, sodium and lithium. The plots are parallel. Correct ranking of the targets according to their work function, greatest first, will be :

The energy that should be added to an electron to reduce its de Broglie wavelength from

\[10^{-10}m\]  to \[0.5\times 10^{-10}m\] m will be :

A radioactive reaction is \[_{92}U^{238}\to _{82}Pb^{206}\] . How many α and β particles are emitted ?