The blackboard seems black because it

examrobotsa's picture
Q: 19 (CDS-I/2011)
The blackboard seems black because it

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,21,29,10,21,8,11

keywords: 

{'blackboard': [0, 0, 0, 1], 'black colour': [0, 0, 0, 2], 'colour': [11, 6, 13, 28]}

The correct answer is option 2 - the blackboard does not reflect any color. When we see an object, we perceive its color based on light that is reflected off of it. Different colors of light have different wavelengths, and when light hits an object, it gets absorbed or reflected based on the object`s properties.

In the case of a blackboard, it appears black because it absorbs most of the light that falls on it and reflects very little back to our eyes. Black objects are able to absorb a wide range of wavelengths of light, including all visible colors, which is why they appear black to us. Since the blackboard absorbs all colors and reflects very little, it does not appear to reflect any color and therefore looks black.

Option 1 is incorrect because if the blackboard reflected every color, it would appear white or neutral, not black. Option 3 is incorrect because black is not a color that can be absorbed. Option 4 is also incorrect because black is not a color that can be reflected.