A laser beam can be sharply focused because it is:
Correct answer: D. Highly directional
- A. Highly coherent
- B. Plane polarized
- C. Intense
- D. Highly directional
Explanation
A laser beam is sharply focused primarily because it is highly directional. This means the light emitted is concentrated along a narrow path, maintaining intensity over distance with minimal spreading due to diffraction. This is in contrast to ordinary light sources, which tend to spread out significantly.While coherence is a defining feature of lasers, making the light waves consistent in phase, it is not the primary reason for the beam's focusability. Plane polarization involves the orientation of light waves and does not affect the beam's focus. Lastly, while intensity refers to the power of the laser, it doesn't influence the beam's directionality or focus.
This question appeared on the ETEA MDCAT 2015 paper, which you can sit online with every answer explained.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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