Question

A krypton laser produces a cylindrical red laser beam 2.40 mm in diameter with 1.70 W of power. What is the light intensity 1.76 m away from the laser?

Answer 1

Answer:

$I=3.75\times 10^5 W/m^2$

Explanation:

Given that

Diameter of laser beam d= 2.4 mm

Radius of laser beam r= 1.2 mm

Power P =1.7 W

We know that intensity(I) of laser beam given as follows

$I=\dfrac{P}{\pi r^2}$

Now by putting the values

$I=\dfrac{P}{\pi r^2}$

$I=\dfrac{1.7}{\pi \times 0.0012^2}$

So

$I=3.75\times 10^5 W/m^2$

So the intensity at 1.76 m away from laser

$I=3.75\times 10^5 W/m^2$