speed of light c=3.0×10^8 m/s]

A particle A of mass ‘m’ and charge ‘q’ is accelerated by a potential difference of 50 V. Another particle B of mass ‘4 m’ and charge ‘q’ is accelerated by a potential difference of 2500 V. The ratio of de-Broglie wavelengths λA/λB is close to : A 2 mW laser operates at a wavelength [...]

If the de-Broglie wavelength of an electron is equal to 10^–3 times the wavelength of a photon of frequency 6 × 10^14 Hz then the speed of electron is equal to : Speed of light = 3 × 10^8 m/s Planck’s constant = 6.63 × 10^–34 J.s Mass of electron = 9.1 × 10^–31 kg [...]

A metal plate of area 1×10^−4m^2 is illuminated by a radiation of intensity 16 mW/m^2. The work function of the metal is 5eV. The energy of the incident photons is 10 eV and only 10% of it produces photo electrons. The number of emitted photo electrons per second and their maximum energy, respectively, will be [...]

A 2 mW laser operates at a wavelength of 500 nm. The number of photons that will be emitted per second is : [Given Planck’s constant h=6.6×10^−34Js, speed of light c=3.0×10^8 m/s] A 2 mW laser operates at a wavelength of 500 nm. The number of photons that will be emitted per second is : [...]