it would not appear green
Green objects would appear green and red objects would appear very dark.
Green.
it would appear black.
While the ball would still be green it will appear black. Anything green absorbed all colours except green. The green light is reflected to your eyes which makes it look green. Thus in red light (with no green in it) the red will be absorbed and no green light can be reflected to your eyes so the ball will look black.
Green.
The red object would appear black because it would not reflect any of the green light shining on it. Green light is the complementary color of red, meaning the object would absorb all the green light and not reflect any color back to our eyes.
A lemon would appear green under green light because the object reflects the color of light that it does not absorb. In this case, a lemon's yellow color would absorb all other colors except green, which it would reflect.
A cyan ball would appear dark or dim under green light because cyan is composed of blue and green light, so without the blue light component, the ball would only reflect the green light, resulting in a darker appearance.
Green light - Green, White light - Green, Red light - Black
Green.
The grass would appear black under orange lights because green objects appear black under light that does not include green wavelengths. Orange lights contain little to no green light, causing green objects like grass to absorb most of the light and appear as black.
In green light, a red book would appear black. Green light does not contain any red wavelengths to reflect off the red book, so it would absorb most of the green light and appear black instead.