Đề kiểm tra giữa kì và Đáp Án môn vật lý 2

observed for stopping voltages less than 1.0 V.What is the wavelength of the new light source?... Say the work function of a surface is 2 eV and lightof wavelength 413 nm hits it.. What'

observed for stopping voltages less than 1.0 V.What is the wavelength of the new light source?

Say the work function of a surface is 2 eV and light

of wavelength 413 nm hits it What's

the maximum kinetic energy of the emittedelectrons?

A laser beam with λ= 630 nm has 2 mW of power

If it goes to a perfect photo detector,

how many photons per second will be detected?(a) 6.7 × 10-11/s

(b) 3.94 × 10-3 /s

(c) 1.96 /s

What is the maximum wavelength of light λ max

that can be used to eject electrons from

(e) 680 nm

7)

If one uses photons with energy 5.82 eV, the

stopping voltage, Vstop, that must be applied

to stop the photoemitted electrons is

A photon in light beam A has twice the energy of aphoton in light beam B The ratio

pA/pB of their momenta is:

be made smaller by using:

A higher frequency radiation

B lower frequency radiation

C more massive particles

D less massive particles

E particles with greater charge

A the frequency of the incident light

B the speed of the electron

C the scattering angle

D the electron recoil energy

E none of the above

monochromatic light source is used, and current isobserved for stopping voltages less than 1.0 V.What is the wavelength of the new light source?

· Say the work function of a surface is 2 eV and light

of wavelength 413 nm hits it What's the maximum kinetic energy of the emitted electrons?

· A laser beam with λ= 630 nm has 2 mW of power.

If it goes to a perfect photo detector, how many photons per second will be detected?

(a) 6.7 × 10⁻¹¹/s