Monochromatic radiation of wavelength `640.2 nm(1nm=10^-9 m)` from a neon lamp irradiates a photosensitive mateiral made of caesium or tungsten. The stopping voltage is measured to be 0.54 V. The source is replaced by an iron source and its 427.2 nm line irradiates the same photocell. predict the new stopping voltage.

Ultraviolet light of wavelength 2271 oversetcircA from a 100 W mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is -1.3 V, estimate the work function of the metal.

In figure S is a monochromatic point source emitting light of wavelength lambda=500 nm. A thin lens of circular shape and focal length 0.10 m is cut into two identical halves L_(1) and L_(2) by a plane passing through a doameter. The two halves are placed symmetrically about the central axis SO with a gap of 0.5 mm. The distance along the axis from A to L_(1) and L_(2) is 0.15 m , while that from L_(1) and L_(2) to O is 1.30 m. The screen at O is normal to SO. (a) If the 3^(rd) intensity maximum occurs at point P on screen, find distance OP.

In figure S is a monochromatic point source emitting light of wavelength lambda=500 nm. A thin lens of circular shape and focal length 0.10 m is cut into two identical halves L_(1) and L_(2) by a plane passing through a doameter. The two halves are placed symmetrically about the central axis SO with a gap of 0.5 mm. The distance along the axis from A to L_(1) and L_(2) is 0.15 m , while that from L_(1) and L_(2) to O is 1.30 m. The screen at O is normal to SO. (b) If the gap between L_(1) and L_(2) is reduced from its original value of 0.5 mm, will the distance OP increases, devreases or remain the same?

A mercury lamp is a convenient source for studying frequency dependence of photoelectric emission, since, it gives a number of spectral lines ranging from the UV to the red end of the visible spectrum. In our experiment with rubidium photo-cell, the following lines from a mercury source were used: lambda_1 = 3650 oversetcircA , lambda_2=4047 oversetcircA , lambda_3=4358 oversetcircA , lambda_4=5461 oversetcircA , lambda_5=6907 oversetcircA The stopping voltages respectively were measured to be V_0=1.28 V , V_0.95V , V_0=0.74V , V_0=0.16 , V_0=0V The threshold frequency and work function for the material.

A mercury lamp is a convenient source for studying frequency dependence of photoelectric emission, since, it gives a number of spectral lines ranging from the UV to the red end of the visible spectrum. In our experiment with rubidium photo-cell, the following lines from a mercury source were used: lambda_1 = 3650 oversetcircA , lambda_2=4047 oversetcircA , lambda_3=4358 oversetcircA , lambda_4=5461 oversetcircA , lambda_5=6907 oversetcircA The stopping voltages respectively were measured to be V_0=1.28 V , V_0.95V , V_0=0.74V , V_0=0.16 , V_0=0V Determine the value of Planck's constant h.