Question
Thu October 27, 2011 By: Saheli Rao

sir,what do u mean by electromangnetic induction? sir,in the case of black board it absorbs all the light that falls on it,no light is reflected,so shoud it not be invisible,since no light from it is received by our eyes,so object will not be seen?

Expert Reply
Fri October 28, 2011
The phenomenon of generating current or e.m.f by changing magnetic fields is called Electromagnetic Induction.
When we see something, the light from that object reflects and enters our eyes. This light interects with cones and rods in our eyes. Rods can detect only black and white while making something appear invisible means that your eyes can't detect it. A black object appears black because it is absorbing the light, which is detectable to our eyes – that is, the absence or reduction of light is detectable.
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