The spectrum obtained from an electric lamp or a red-hot heater is:

In a photocell,bichromatic light of wavelengths $2475 \ \mathring{A}$ and $6000 \ \mathring{A}$ is incident on a cathode whose work function is $4.8 \ eV$. If a uniform magnetic field of $3 \times 10^{-5} \ T$ exists parallel to the plate,the radius of the path described by the photoelectron will be ............ $cm$ (mass of electron $= 9 \times 10^{-31} \ kg$).

The ratio of the wavelength of a photon of energy $E$ to that of an electron of the same energy is ($m=$ mass of an electron,$c=$ speed of light,$h=$ Planck's constant).

The spectrum of an oil flame is an example of:

An electron is moving through a field. It is moving $(i)$ opposite to an electric field and $(ii)$ perpendicular to a magnetic field as shown. For each situation,determine the de-Broglie wavelength of the electron.

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 -