Huh. How about "turn on the light"?
Also when I answered with this, the correct answer given was "kindle the light", which is very unnatural, even if you are lighting a real fire with kindling!
Not fixed yet. Reported it. "Turn on the light" didn't work on 5/10/18.
I think it might be that they have to fix each instance of the sentence separately. So for example, you might have done the text input version and I might have done the word tiles version,which was already fixed. Just a guess...
Put on the light is exactly the same as switch on the light and should be acceptable
The offered answer is in plural(lights).
Can it stand for singular (light)as well?
Yes! The noun "taa" is in class 9/10, so the singular is the same as the plural.