Home
Class 12
PHYSICS
The eye can detect 5xx10^(4) photons (m^...

The eye can detect `5xx10^(4)` photons `(m^2s)^(-1)` of green light (`lamda=5000A)`, whole ear can detect `10^(-13)Wm^(2)` . As a power detector, which is more sensitive and by what factor?

Text Solution

Verified by Experts

`E=12375/5000=2.475` eV =`4xx10^(-19)` J
`l_"Eye"` =(Photon flux) x (Energy of photon) =`(5xx10^4)xx(4xx10^(-19))approx 2xx10^(-14) (W//m^2)`
Lesser the intensity `rArr ` More sensitive .
`S_"Eye"/S_"Ear"=l_"Ear"/l_"Eye"=10^(-13) /(2xx10^(-14))=5`
Promotional Banner

Topper's Solved these Questions

  • DUAL NATURE OF RADIATION AND MATTER

    AAKASH INSTITUTE ENGLISH|Exercise Try Yourself|41 Videos

  • DUAL NATURE OF RADIATION AND MATTER

    AAKASH INSTITUTE ENGLISH|Exercise ASSIGNMENT SECTION A. Objective (Only one answer)|50 Videos

  • CURRENT ELECTRICITY

    AAKASH INSTITUTE ENGLISH|Exercise ASSIGNMENT SECTION-J|10 Videos

  • ELECTRIC CHARGES AND FIELDS

    AAKASH INSTITUTE ENGLISH|Exercise comprehension|3 Videos

Similar Questions

Explore conceptually related problems

The human eye can barely detect a yellow lings ( lamda=6000A ) that delivers 1.7xx10^(-18) W to the retina. The number of photons per second falling on the eye is nearest to

A monochromatic beam of light (lamda=4900A) incident normally upon a surface produces a pressure of 5xx10^(-7)Nm^(-2) on it. Assume that 25% of the light incident in reflected and the rest absorbed. Find the number of photons falling per second on a unit area of thin surface

The faintest sound the human ear can detect at a frequency of 1000 Hz correspond to an intensity of about 1.00xx10^-12(W)/(m^2) , which is called threshold of hearing. The loudest sounds the ear can tolerate at this frequency correspond to an intensity of about 1.00(W)/(m^2) , the threshold of pain. Detemine the pressure amplitude and displacement amplitude associated with these two limits. Take speed of sound =342(m)/(s) and density of air =1.20(kg)/(m^3)

Threshold frequency of a metal is 5xx10^(13)s^(-1) upon which 1xx10^(14)s^(-1) frequency light is focused. Then the maximum kinetic energy of emitted electron is

At t=O, light of intensity 10^(12) photons/ s-m^(2) of energy 6eV per photon starts falling on a plate with work founction 2.5 eV If area of the plate is 2xx10^(-4) m^(2) and for every 10^(5) photons one photoelectron is emitted, charge on the plate at t=25 s is

A 100W bulb has tungsten filament of total length 1.0m and raidius 4xx10^(-5)m . The emiswsivity of the filament is 0.8 and sigma=6.0xx10^(-8)Wm^(-2)K^(-4) . Calculate the temperature of the filament when the bulb is oprating at correct wattage.

two galvanometers of resistance 100Omega and 50Omega , are 10^(-8)A//"div and "2 xx 10^(-5) A/div respectively. In which case the voltage sensitivity is more ?

A bob of mass 10 kg is attached to a wire 0.3 m long. Its breaking stress is 4.8xx10^(7) N//m^(2) . Then area of cross-section of the wire is 10^(-6) m^(2) . What is the maximum angular velocity with which it can be rotated in a horizontal circle?

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

Two sources S_(1) and S_(2) emiting light of wavelenght 600 nm placed a distance 1.0 xx 10^(-2) cm apart. A detector can be moved on line S_(1) P which is perpendicular to S_(1) S_(2) (a) What would be the minimum and maximum path difference at the detector as it moves along line S_(1) P ? (b) Locate the psoition of the farthest minima detected .