How many photons per second are emitted by a monochromatic lightbulb (650 nm) that emits 45 w of power? express your answer using two significant figures. if you stand 17 m from this bulb, how many photons enter each of your eyes per second? assume your pupil is 5.0 mm in diameter and that the bulb radiates uniformly in all directions. express your answer using two significant figures.

The number of photons per second are .

Explanation:

Given that,

Wavelength = 650 nm

Power = 45 W

Distance R= 17 m

Diameter = 5.0 mm

We need to calculate the number of photon per second emitted by light bulb

Using formula of energy

The power is

Put the value of E

Put the value into the formula

We need to calculate the surface area

Using formula of area

We need to calculate the number of photons entering into eye

Hence, The number of photons per second are .

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j