# Vanda

Popular questions and responses by Vanda
1. ## Physics

A special kind of light bulb emits monochromatic light of wavelength 630 nm. Electrical energy supplied to it at the rate of 60W, and the bulb is 93% efficient at converting that energy into light energy. How many photons are emitted by the bulb during its

asked on March 18, 2011
2. ## Physics urgent!!!!

Electrons in a beam incident on a crystal at an angle of 30ͦ have kinetic energies ranging from zero to a maximum of 5500 eV. The crystal has a grating space d=0.5 Aͦ, and the reflected electrons are passed through a slit .Find the velocities of the

asked on April 8, 2011
3. ## Physics

The seeing ability, or resolution, of radiation is determined by its wavelength. If size of an atom is of the order of 0.1 nm, how fast must an electron travel to have a wavelength small enough to “see” an atom?

asked on April 7, 2011
4. ## Physics

a) If the work function for a certain metal is 1.8 eV, What is the stopping potential for electrons ejected from the metal when light of wavelength 400 nm shines on the metal? b) What is the maximum speed of the ejected electrons?

asked on March 20, 2011
5. ## Physics

Light is incident on a glass-air interface from the glass side (n=1.5), and researchers want to use the evanescent field on the air side (n=1.0) to excite the molecules adhered to the surface. It is desired that the evanescent field extend a distance δ =

asked on October 9, 2011
6. ## Physics

Electrons in a beam incident on a crystal at an angle of 30ͦ have kinetic energies ranging from zero to a maximum of 5500 eV. The crystal has a grating space d=0.5 Aͦ, and the reflected electrons are passed through a slit .Find the velocities of the

asked on April 8, 2011
7. ## Physics

Gamma rays of photon energy 0.511 MeV are directed onto an aluminum target and are scattered in various directions by loosely bound electrons there.a) What is the wavelength of the incident gamma rays? b) What is the wavelength of the gamma rays scattered

asked on March 22, 2011
8. ## Physics

X-radiation from a molybdenum target (0.626 A) is incident on a crystal with adjacent atomic planes spaced 4.00x10(-10) m apart. Find three smallest angles at which intensity maxima occur in the diffracted beam?

asked on March 22, 2011
9. ## Physics

Find the approximate gravitational red shift in 500 nm light emitted by a compact star whose mass is that of sun but whose radius is 10 km.

asked on March 22, 2011
10. ## Physics

Gamma rays of photon energy 0.511 MeV are directed onto an aluminum target and are scattered in various directions by loosely bound electrons there.a) What is the wavelength of the incident gamma rays? b) What is the wavelength of the gamma rays scattered

asked on March 21, 2011
11. ## Physics

X-radiation from a molybdenum target (0.626 A) is incident on a crystal with adjacent atomic planes spaced 4.00x10(-10) m apart. Find three smallest angles at which intensity maxima occur in the diffracted beam?

asked on March 21, 2011
12. ## Physics

Gamma rays of photon energy 0.511 MeV are directed onto an aluminum target and are scattered in various directions by loosely bound electrons there.a) What is the wavelength of the incident gamma rays? b) What is the wavelength of the gamma rays scattered

asked on March 21, 2011
13. ## Physics

Find the approximate gravitational red shift in 500 nm light emitted by a compact star whose mass is that of sun but whose radius is 10 km.

asked on March 21, 2011
14. ## Physics

Find the approximate gravitational red shift in 500 nm light emitted by a compact star whose mass is that of sun but whose radius is 10 km.

asked on March 21, 2011
15. ## Physics

The work function for potassium and cesium are 2.25 and 2.14 eV, respectively. a) Will the photoelectric effect occur for either of these elements with incident light of wavelength 565 nm? b) With light of wavelength 518 nm ?

asked on March 18, 2011