Answer:
3.73 * 10^16 photons/sec
Explanation:
power supply = 3.0 V
Emits 440 nm blue light
current in LED = 11 mA
efficiency of LED = 51%
<u>Calculate the number of photons per second the LED will emit </u>
first step : calculate the energy of the Photon
E = hc / λ
=( 6.62 * 10^-34 * 3 * 10^8 ) / 440 * 10^-9
= 0.0451 * 10^-17 J
Next :
Number of Photon =( power supply * efficiency * current ) / energy of photon
= ( 3 * 0.51 * 11 * 10^-3 ) / 0.0451 * 10^-17
= 3.73 * 10^16 photons/sec
Answer:
About 13 cm
Explanation:
We are given that
Length of cylinder,l=15 cm=
1 m=100 cm
h=4 cm=
Horizontal velocity of the existing water stream=
Where 
Using the formula

h'=l-h=15-4=11 cm=
Initial velocity of water stream,u=0

Distance, d=vt
Using the formula

