Red or blue. The reason a red filter looks and is red, is because only red light comes through it, and the same can be said about a blue filter allowing only blue light through. Other colors are absorbed by the dyes in the filter. If white light enters a red filter, then red light comes out, and the same goes for blue.
It depends on what kind of filter, e.g. a blue filter absorbs everything except blue light, so only blue light comes out, which is why the filter looks blue, and is referred to as a "blue filter".
A green object appears black when viewed through a red filter (here a red filter means red light) because green object can only reflect green color and absorb all the other colors so in the red light it will definitely appear black.
Since the filter allows only blue light to pass through, anything you see through the filter appears either blue or black. Blue if there's any blue light coming from it, or black if there isn't any.
green
It will look black, or green, depending on the hue of the red. A green filter blocks the red light but no red object is reflecting solely in the red wavelengths, and any non-red light will appear green through the filter.
When a yellow book is viewed through a green filter, the filter will absorb most of the yellow light but allow green light to pass through. As a result, the book may appear darker and its yellow color may become less vibrant when viewed through the green filter.
Black, or nearly so. The apple reflects only green light, the red filter only lets red light through, so nothing reaches the eye.
It depends on what kind of filter, e.g. a blue filter absorbs everything except blue light, so only blue light comes out, which is why the filter looks blue, and is referred to as a "blue filter".
A green object appears black when viewed through a red filter (here a red filter means red light) because green object can only reflect green color and absorb all the other colors so in the red light it will definitely appear black.
Since the filter allows only blue light to pass through, anything you see through the filter appears either blue or black. Blue if there's any blue light coming from it, or black if there isn't any.
green
green
A spectroscope is a device for producing and recording spectra for examination. When light given off by a simple burning substance is viewed through a spectroscope, a certain color will appear.
red apples
Purple will the object be
The optical illusion of the moon changing color is due to the angle through the atmosphere that the moon is viewed at. If there is pollution in the air and the moon is at a low angle, then it will appear orange, brown, or red.
It will look black, or green, depending on the hue of the red. A green filter blocks the red light but no red object is reflecting solely in the red wavelengths, and any non-red light will appear green through the filter.