Question

10. For a typical laser, the angular spread of its beam is about
(A) 1 second
(B) 1 minute
(C) 1 mm per meter
(D) 1 mm per centimetre​

Answer 1

Explanation:

Theoretically the angle of spread of the laser beam, in radians, would be its narrowest diameter divided by the wavelength of light. If the beam were 1 mm in diameter then its angular spread would be: A = L/d = 6 x 10-7 m/10-3 m = 6 x 10-4 radians or 60 milliradians. d = A x D = 6 x 10 -4 x 10 = 6 x 10 -3 m = 6 mm.