What is the number of photon of light with a wvelengthof 4000 pm that provide 1 J of energy ?

Explanation

According to Planck.s quantum theory
`E = nhv = mh (c)/(lamda )`
` 1 J = ( n xx 6. 626 xx 10 ^(-34) xx 3 xx 10 ^(8))/(4000 xx 10 ^(-12))`
`n = ( 4000)/( 19 . 878) xx 10 ^(34 - 20) `
`or ,n = 2. 0 12 xx 10 ^(16)` photons