When a surface is irradiated with light of wavelength $4950 o A$ , a photoncurrent appears which vanishes if a retarding potential greater than 0.6 V is applied across the photo tube. When a different source of light is used, it is found that the critical retarding potential is changed to 101 V. If the photoelectrons (after emission from the surface) are subjected to a magnetic field of 10 T. The work function of the emitting surface is $3.04 \times 10^{- X} V$ . Find X?

Question

When a surface is irradiated with light of wavelength $4950 o A$ , a photoncurrent appears which vanishes if a retarding potential greater than 0.6 V is applied across the photo tube. When a different source of light is used, it is found that the critical retarding potential is changed to 101 V. If the photoelectrons (after emission from the surface) are subjected to a magnetic field of 10 T. The work function of the emitting surface is $3.04 \times 10^{- X} V$ . Find X?

Toppr Admin · Accepted Answer

Einstein-apos-s equation for photoelectric effect ishc-x3BB-W-eV06-6-xD7-10-x2212-34-xD7-3-xD7-1084950-xD7-10-x2212-10-W-1-6-xD7-10-x2212-19-xD7-0-6W-3-04-xD7-10-x2212-19Vhence X - 19

Einstein's equation for photoelectric effect ishcλ=W+eV06.6×10−34×3×1084950×10−10=W+1.6×10−19×0.6W=3.04×10−19Vhence X = 19

Einstein's equation for photoelectric effect is
$\frac{h c}{λ} = W + e V_{0}$
$\frac{6.6 \times 10^{- 34} \times 3 \times 10^{8}}{4950 \times 10^{- 10}} = W + 1.6 \times 10^{- 19} \times 0.6$
$W = 3.04 \times 10^{- 19} V$
hence X = 19