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PHYSICS EXPERIMENT. Group 2. Nikita Tokas ( 303/B/12 ) Nitika Agarwal ( 305/B/12 ) Nitin Saxena ( 306/B/12 ) Of COE-2, Batch of 2012-16. AIM. To determine the resolving power of the telescope. APPARATUS REQUIRED. A telescope A powerful source of monochromatic light
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PHYSICS EXPERIMENT Group 2 Nikita Tokas (303/B/12) NitikaAgarwal (305/B/12) Nitin Saxena(306/B/12) Of COE-2, Batch of 2012-16
AIM • To determine theresolving power of thetelescope.
APPARATUS REQUIRED • A telescope • A powerful source of monochromatic light • Variable rectangular aperture • Measuring scale • Micrometer microscope • Sheet of plate glass coated with a tin foil containing two fine parallel lines
Telescope Telescope is a device which is used to view distant objects. Resolving power of telescope is the ability of telescope to produce distinct images of two nearby objects. It is defined as the reciprocal of the least angular separation between two distant objects, with the base of angle at the telescope, such that the objects appear separated when seen through telescope.
THEORY • For a telescope fitted with a rectangular aperture, the limiting angle of resolution is given by: = OO’/u = /d where OO’ = distance between the two objects u = distance of the object from objective of the telescope = wavelength of light coming from the objects d = width of aperture( placed below the objective of telecscope) for just resolution of the two objects • The reciprocal of the limiting angle of resolution is the resolving power.
EXPERIMENTAL SETUP • SOURCE : http://www.scribd.com/doc/32219885/Resolving-Power-of-Telescope-by-Mr-charis
PROCEDURE • The given double slit is fitted to a slit stand and place closer to the sodium vapor source, such that the two slits are clearly visible from the telescope. • Place the telescope at a distance of 1 meter from the double slit and fix the micrometer eyepiece to the objective of the telescope with its slit completely open.
Observing through the telescope adjust the focus using rock and pinion screw of the telescope so that the two slits are clearly visible and decrease the width of the slit of the micrometer eyepiece slowly till the two slits come closer and closer to attain thejust resolved position. Note the readings of the micrometer eye piece. • Further decrease the width of the adjustable slit such that the field of view becomescompletely dark and note the readings of the micrometer eye piece. • Repeat the 2nd, 3rd and 4th steps by increasing the distance of the telescope in the steps of 10 cm and calculate the value of width of the slit in just resolved position.
OBSERVATIONS • = 5500 Å • 00’ = 2 x 10-3 m
CALCULATIONS • Mean Theoretical Resolving Power = 341.01 • Mean Practical Resolving Power = 350 • Percentage Error = |Theoretical R.P. – Practical R.P.| X 100 Theoretical R.P. = 2.64 %
RESULT • The expression for the resolving power of the telescope fitted with a rectangular aperture has been verified.
PRECAUTIONS AND SOURCES OF ERRORS • The mechanical adjustments of the telescope must be correct. • The plane of the target consisting of two bright linear sources should be vertical and so also these sources. • The axis of the telescope should be horizontal and should meet the target normally. • Due care must be taken while measuring the width of the aperture and distance between two linear sources with a microscope. Avoid back lash error during the course of measurements made with it. • The screw attached to the variable width aperture should be handled gently.
BIBLIOGRAPHY • A Textbook of Practical Physics By : InduPrakash, Ram Krishna, A.K. Jha • www.google.com