The minimum intensity of light to be detected by human eye is `10^(-10) W//m^(2)`. The number of photons of wavelength `5.6 xx 10^(-7) m` entering the eye , with pupil area `10^(-6) m^(2)` , per second for vision will be nearly

Minimum light intensity that can be perceived by normal human eye is about 10^(-10) Wm^(-2) . What is the minimum number of photons of wavelength 660 nm that must enter the pupil in one second, for one to see the object?Area of cross-section of the pupil is 10^(-4)m^(2) ?

Minimum light intensity that can be perceived by normal human eye is about 10^-10 W m^-2 . What is the minimum number of photons of wavelength 660 nm that must enter the pupil in one second, for one to see the object ? Area of cross-section of the pupil is 10^-4 m^2 ?

The ratio of energy of photon of a wavelength 10^(-10) m that of photon of wavelength 5 xx 10^(-8) m is

The pupil allows light to pass through it and has a diameter of 2xx10^(-3)m. If minimum light intensity that should enter the eye is 1.8xx10^(-10) W//m^(-2) , then find the number of photon in visible range must enter the pupil to have vision. Wavelength of photon in visible range can be taken as 5,500Å .

The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100 W is (taking h = 6 xx 10^(-34) sec )

The number of photons of light of barv =2.5×10^6m^(−1) necessary to provide 2 J of energy are:

The speed of light is 3 xx 10^8m//sec . Calculate the frequency of red light of wavelength of 6.5 xx 10^-7 m.