List the possible sources of error in refraction at plane surface
List the possible sources of error in refraction at plane surface
The Correct Answer and Explanation is:
Possible Sources of Error in Refraction at a Plane Surface
- Parallax Error
- Incorrect Normal Drawing
- Poor Quality or Dirty Glass Slab
- Misalignment of Pins
- Inaccurate Angle Measurements
- Light Scattering or Diffraction
- Uneven Surface or Thickness of Glass Slab
- Ambient Light Interference
- Instrumental Errors (e.g., protractor, ruler)
- Human Observation Error
Explanation
Refraction at a plane surface, such as when light passes through a rectangular glass slab, is governed by Snell’s Law. While the principles are straightforward, practical experiments often encounter various sources of error that affect accuracy and reliability.
Parallax error is common when aligning pins or observing through the glass slab. If the observer’s eye is not perpendicular to the plane of the paper, it may cause incorrect alignment, leading to inaccurate tracing of light paths.
Another major source is the incorrect drawing of the normal line at the point of incidence. Since the angle of incidence and refraction are measured relative to the normal, any deviation in its direction will cause a significant error in the measured angles.
The quality of the glass slab also matters. Imperfections such as bubbles, dirt, or scratches can distort the light path. Additionally, if the slab is not of uniform thickness or has slightly curved surfaces, the assumptions about planar refraction may not hold true.
Misalignment of pins (used to trace the incident and emergent rays) introduces error when the light paths are not accurately marked. This is usually due to imprecise pin placement or shifting during the experiment.
Measurement inaccuracies, such as using a worn-out or imprecise protractor or ruler, can also skew results. Moreover, ambient lighting may cause reflections or glare, making it hard to see the light path or pins clearly.
Lastly, human observational errors, such as inconsistent viewing angles or hand movement while drawing, can all contribute to deviations in the expected results.
To minimize these errors, proper experimental setup, careful alignment, clean equipment, and precise instruments must be used, and multiple trials should be averaged for reliability.
