Answer:
Bulb
Explanation:
Bulb and fluorescent tubes convert electrical energy into light energy. The best alternative in this case will be a bulb. The switch controls flow of current hence used to put the circuit on and off but doesn't do any conversion.
17. a
18. c
19. a
20. c
21. c
Green has a shorter wavelength.
It is very easy..let me tell you.. there are seven colors in the rainbow. Isn't it?
According to their decreasing order of wavelength , they are:
Red
Orange
Yellow
Green
Blue
Indigo
Violet.
It is as simple as that to remember....
Answer: public service announcement
Explanation: