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To Determine Radius of Curvature of A Given Spherical Surface by A Spherometer

This document provides instructions for using a spherometer to determine the thickness of a glass plate or the radius of curvature of a convex surface. The spherometer works on the principle of a micrometer screw and is used to measure small thicknesses or radii of curvature. To use it, observations of the circular and disc scale readings are made with the object placed on the spherometer and calculations are done to determine the thickness or radius based on the readings and spherometer theory. Precautions like minimizing friction and excess rotation of the screw are listed to improve accuracy.

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Yash Tandon
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2K views3 pages

To Determine Radius of Curvature of A Given Spherical Surface by A Spherometer

This document provides instructions for using a spherometer to determine the thickness of a glass plate or the radius of curvature of a convex surface. The spherometer works on the principle of a micrometer screw and is used to measure small thicknesses or radii of curvature. To use it, observations of the circular and disc scale readings are made with the object placed on the spherometer and calculations are done to determine the thickness or radius based on the readings and spherometer theory. Precautions like minimizing friction and excess rotation of the screw are listed to improve accuracy.

Uploaded by

Yash Tandon
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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BLANK SIDE(WITH PENCIL ONLY) RULED SIDE(PEN ONLY)

1 AIM 1 AIM

2 DIAGRAM 2 APPARATUS

3 OBSERVATION AND CALCULATIONS 3 THEORY

4 RESULT/CONCLUSION 4 PRECAUTIONS

5 sources of error

*FOLLOW WRITING PATTERN STRICTLY

*NO ERROR IN YOUR OBSERVATIONS SO OBSERVED VALUE AND TRUE VALUE ARE SAME

Aim
To determine radius of curvature of a given spherical surface by a spherometer.

To determine the thickness of a glass plate using a spherometer.

Apparatus 
Spherometer, convex surface (it may be unpolished convex mirror), a big size plane glass slab or plane mirror.
A glass plate.

Diagram 
Theory 
It works on the principle of micrometre screw (Section 2.09) It is used to measure either very small thickness or
the radius of curvature of a spherical surface that is why it is called a spherometer.

Observations 

Circular scale reading No of disc scale


No of complete Total reading
Object On plane divisions in incomplete
On concave rotation on plane = (n x p) +(x x
placed glass rotation X=(a-b) or
surface(initial) glass sheet(n) l.c)mm
sheet(final) (100+a)-b
       
       
  Glass strip        t =
       
       
       
       
  Concave surface        h =
       
       
Calculation

The thickness of the glass plate, t = --------------- mm = --------------------m .


Mean value of h = -----------------------mm.

Radius of curvature of the spherical surface    = ---------------cm=................m

Result

The thickness of glass strip =  ------------m


The radius of curvature of the given concavesurface = -----------------m 

Precautions 

1. The screw should move freely without friction.


2. The screw should be moved in same direction to avoid back-lash error of the screw.
3. Excess rotation should be avoided.

Sources of error 

1. The screw may have friction.


2. The spherometer may have back-lash error.
3. Circular (disc) scale divisions may not be of equal size.

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