Suppose y varies directly with x. If y=6 when x=-2, find x when y=15

5

Step-by-step explanation:

y = 6 when x = 2

y = 3x

when y = 15

15 = 3x

3x = 15

x = 15/3

x = 5

Explanation :

The energy of any light is given by :

Where

h is the Planck constant    

c is the speed of light

is the wavelength of light.  

So, it is clear that the energy depends inversely on the wavelength of the light.

The given data shows that the wavelength of violet light is least. So, the energy of violet light is maximum.

But out of given options, the wavelength of the blue light is small. So, the blue light will transmits most energy.

So, the correct option is (A).