A plane wave of intensity 0 9 W/cm2 illuminates a perfectly absorbing cylinder of radius 5 cm and height 10 - Physics - Dual Nature Of Radiation And Matter

Question

A plane wave of intensity 0 9 W/cm2 illuminates a
perfectly absorbing cylinder of radius 5 cm and height 10 cm as
shown in figure The force that light exerts on the cylinder in
micro newton is
(A) 0 3 (B) 3 0 (C) 0 6 (D) 0 8

Debalina Deb · Accepted Answer

Dear student,

The force that light exerts on the absorbing surfaceF=Area×Intensity of lightspeed of light(here only the surface of the cylindrical surface will absorbes the light)F=2πrh×IcF=2π×5×10×0
93×108=94 2×10-8=0 94×10-6 NF=0
94 μNr=5cmh=10cmI=0
9W/cm2r×h×I=(5×10×0
9)Wand unit of F=unit of 2πrh×Ic=watt/ms-1= Newton

Regards,

A plane wave of intensity 0.9 W/cm2 illuminates a perfectly absorbing cylinder of radius 5 cm and height 10 cm as shown in figure. The force that light exerts on the cylinder in micro newton is (A) 0.3 (B) 3.0 (C) 0.6 (D) 0.8

A plane wave of intensity 0.9 W/cm² illuminates a perfectly absorbing cylinder of radius 5 cm and height 10 cm as shown in figure. The force that light exerts on the cylinder in micro newton is
(A) 0.3 (B) 3.0 (C) 0.6 (D) 0.8