Home
Class 12
PHYSICS
The human eye has an approximate angluar...

The human eye has an approximate angluar resolution of `phi=5.8xx10^(-4)` rad and a typical photoprinter prints a minimum of 300 dpi ( dots per inches, 1 inch =2.54 cm). At what minimal distance z should a printed page be held so that one does not see the individual dots.

A

`37.3`

B

`44.1`

C

`25`

D

`14.7`

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Topper's Solved these Questions

  • WAVES OPTICS

    AAKASH SERIES|Exercise EXERCISE -III (POLARISITION)|10 Videos
  • WAVES OPTICS

    AAKASH SERIES|Exercise EXERCISE -III (DOPPLER EFFECT IN LIGHT, INTERFERENCE)|25 Videos
  • WAVES

    AAKASH SERIES|Exercise EXERCISE-III (Doppler effect :)|15 Videos

Similar Questions

Explore conceptually related problems

The human eye has an approximate angular resolution of phi = 5.8xx10^(-4) rad and a typical photo printer prints a minimum of 300 dpi (dots per inch, = 2.54 cm ). Aminimum distance 'z' should a printed page be held so that one doesnot see the indivdual dots is ______ .

The human eye has an approximate angular resolution of phi = 5.8xx10^(-4) rad and a typical photo printer prints a minimum of 300 dpi (dots per inch, = 2.54 cm ). Aminimum distance 'z' should a printed page be held so that one doesnot see the indivdual dots is ______ .

A mercury arc lamp provides 0.10 W of UV radiation at a wavelength of lambda = 2537Å (all other wavelenghts having been absorbed by filters). The cathode of photoelectric device (a photo-tube) consists of potassium and has an effective area of 4cm^(2) . The anode is located at a distance of 1 m from radiation source. The work function for potassium is phi_(0) = 2.22eV . (a) According to classical theory, the radiation from the arc spreads out uniformly in space as spherical wave. What time of exposure to the radiation should be required for a potassium atoms(radius 2 Å) in the anode to accumulate sufficient energy to eject a photo-electron? (b) What is the energy of a single photon from the source? (C) What is the flux of photons(number per second) at the cathode? To what saturation current does this flux correspond if the photo-conversion efficiency is 5% (i.e. if each photon has a probability of 0.05 of ejecting an electron). (d) what is the cutt off potential V_(0) ?

When an object moves through a fluid, as when a ball falls through air or a glass sphere falls through water te fluid exerts a viscous foce F on the object this force tends to slow the object for a small sphere of radius r moving is given by stoke's law, F_(w)=6pietarv . in this formula eta in the coefficient of viscosity of the fluid which is the proportionality constant that determines how much tangential force is required to move a fluid layer at a constant speed v, when the layer has an area A and is located a perpendicular distance z from and immobile surface. the magnitude of the force is given by F=etaAv//z . For a viscous fluid to move from location 2 to location 1 along 2 must exceed that at location 1, poiseuilles's law given the volumes flow rate Q that results from such a pressure difference P_(2)-P_(1) . The flow rate of expressed by the formula Q=(piR^(4)(P_(2)-P_(1)))/(8etaL) poiseuille's law remains valid as long as the fluid flow is laminar. For a sfficiently high speed however the flow becomes turbulent flow is laminar as long as the reynolds number is less than approximately 2000. This number is given by the formula R_(e)=(2overline(v)rhoR)/(eta) In which overline(v) is the average speed rho is the density eta is the coefficient of viscosity of the fluid and R is the radius of the pipe. Take the density of water to be rho=1000kg//m^(3) Q. Blood vessel is 0.10 m in length and has a radius of 1.5xx10^(-3) m blood flows at rate of 10^(-7)m^(3)//s through this vessel. The pressure difference that must be maintained in this flow between the two ends of the vessel is 20 Pa what is the viscosity sufficient of blood?