Energy from the sun is received on the earth at the rate of 2 cal per cm² per min. If average wavelength of solar light be taken at 5500 Å, then how many photons are received on the earth per cm² per min ?
\[\left( h=6.6\times 10^{-34}J-s,cal = 4.2 J \right)\]
Monochromatic light of frequency f1 is incident on a photocell and the stopping potential is found to be V1. What is the new stopping potential of the cell if it is radiated by monochromatic light of frequency f2 ?
The correct graph between the maximum energy of a photoelectron and the inverse of wavelength of the incident radiation is given by the curve
A photon and an electron have equal energy E. \[\lambda_{photon}/\lambda_{electron}\] is proportional to
Ultraviolet light of wavelength 300 nm and intensity 1.0 watt/m² falls on the surface of a photosensitive material. If 1% of the incident photons produce photoelectrons, then the number of photoelectrons emitted from an area of 1.0 cm² of the surface is nearly
A photon of wavelength 6630 Å is incident on a totally reflecting surface. The momentum delivered by the photon is equal to
Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays (ν1 > ν2). If the maximum value of kinetic energy of the photoelectrons emitted in the two cases are in the ratio of 1 : k, then the threshold frequency of the metallic surface is :
The ratio of de-Broglie wavelengths of molecules of hydrogen and helium which are at temperature 27°C and 127° respectively is :
The figure shows the variation of photo current with anode potential for a photo-sensitive surface for three different radiations. Let Ia, Ib, and Ic be the intensities and fa, fb and fc be the frequencies for the curves a, b and c respectively :
The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as given below :
