why is it said that the object is placed at "infinity" to form image at focus in a concave mirror?particularly, why not just any distance? why "infinity"? when it is actuallu not
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the position of image formed depends on where the object is placed.
eg - when object is placed at the focus, the image never forms.
when object placed between pole and focus, image formed is virtual.
when object is placed at infinite ( that is very very far) the incident rays are parallel to the centre of curvature. whenever incident rays are parallel to the centre of curvature, they pass through the focus.
therefore, when object is at infinite the incident rays are parallel and go through the focus and the image is formed there
eg - when object is placed at the focus, the image never forms.
when object placed between pole and focus, image formed is virtual.
when object is placed at infinite ( that is very very far) the incident rays are parallel to the centre of curvature. whenever incident rays are parallel to the centre of curvature, they pass through the focus.
therefore, when object is at infinite the incident rays are parallel and go through the focus and the image is formed there
Sandy260:
kind of.
an example is the sun
the rays are coming from infinite ( very far )
(might be annoying) but your example sun.the distance between sun and earth is very much measurable. therefore i believe it should not be considered infinity.
but why is it considered infinity?
infinite here just refers to something that is very far.
alright. i guess i have to justa agree to this.
thanks very much.
your welcome
sun's rays are the best example we can take for an infinite ray
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