What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root-mean-square speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076 u)
(1) 0.028 nm
(2) 0.031 nm
(3) 0.127 nm
(4) 0.0139 nm
About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation at a distance of 1 m from the bulb?
What is the de Broglie wavelength of a bullet of mass 0.040 kg traveling at the speed of 1.0 km/s?
An electron and a photon each have a wavelength of 1.00 nm. The momentum of the electron will be:
(1) Greater than photon.
(2) Equal to the photon.
(3) Less than photon.
(4) None of these.
The work function of cesium metal is 2.14 eV. When light of frequency 6 × 1014 Hz is incident on the metal surface, photoemission of electrons occurs. What is the stopping potential of the metal?
(1) 0.212 V
(3) 0.127 V
(4) 0.311 V
The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?
Monochromatic light of wavelength 632.8 nm is produced by a
helium-neon laser. The power emitted is 9.42 mW. The energy of each photon in the light beam is:
The energy flux of sunlight reaching the surface of the earth is 1.388 × 103 W/m2. How many photons(nearly) per square meter are incident on the Earth per second? Assume an average wavelength of 550 nm.
In an experiment on the photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be . The value of Planck's constant is:
A 100 W sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of sodium light is 589 nm. What is the energy per photon associated with the sodium light?