Question
A laser beam can be focussed on an area equal to the square of its wavelength. A He-Ne laser radiates energy at the rate of 1mW and its wavelength is 632.8 nm. The intensity of focussed beam will be
Answer: Option B
:
B
Area through which the energy of beam passes
=(6.328×10−7)=4×10−13m2
∴I=PA=10−34×10−13=2.5×109W/m2
Was this answer helpful ?
:
B
Area through which the energy of beam passes
=(6.328×10−7)=4×10−13m2
∴I=PA=10−34×10−13=2.5×109W/m2
Was this answer helpful ?
More Questions on This Topic :
Latest Videos
Latest Test Papers
Submit Solution