Physics Lab Manual.doc

AVS Engineering College

Salem - 3

Department of Physics

Laboratory Manual

&

Observations

Reg. Number :

Name

:

List of Experiments:

1. a. Particle size determination using diode Laser

b. Determination of Laser parameters – Wavelength, refractive

index and angle of divergence

c. Determination of Acceptance angle in an optical fiber

2. Lee’s disc method – Thermal conductivity of a Bad Conductor

3. Ultrasonic interferometer – Compressibility of a Liquid

4. Spectrometer grating – Wavelength of the Mercury Spectrum

5. Air Wedge - Thickness of a thin wire

6. Determination of Young’s modulus of the material – Non Uniform

Bending

7. Determination of moment of inertia of disc and Rigidity modulus

of a wire – Torsional Pendulum.

8. Determination of band gap of a semiconductor material.

9. Determination of Young’s modulus of the material – Uniform

Bending

Expt

No

Date

Name of the Experiment

Date of

Completion

Marks

1. a. Particle size determination

Using diode laser

Aim:

To find the particle size of the given using source.

Apparatus Required:

A diode laser, given particle, scale, stand, screen.

Formula:

λm Y2_{m + D}2 1

The size of the particle d = --- meter Ym

Where:

λ – Wave length of the laser source (metre) λ = 670 x 10-9 _m

m - Order of the spectrum

ym – Distance of the nth order from Zeroth order (metre)

D1 – Distance between the particle and the screen (metre)

Procedure:

To find the given particle size (d) :

Order

Ym Mean

Y2_{m D}

1 D21 Y 2_m+D2

1 _d

LHS RHS Ym

No X10-2_{m X10}-2_{m X10}-2_{m X10}-4_{m X10}-2_{m X10}-4_{m X10}-2_{m Metre}

First

Second

First

Second

First

Observation:

Wavelength of the given laser source (λ) = --- Ǻ (or) 10-10_m

Distance between particle and Screen (D1) = --- Cm (or) 10-2m

Result :

1. b. Determination of laser parameters – wavelength,

Refractive index and angle of divergence

Aim:

To determine wavelength of the given laser source angle of divergence using a laser a laser grating.

Apparatus required:

A laser source, laser grating, screen source, scale., etc

Formula:

xm

(i) Wavelength of the given laser λ = --- Ǻ Nm x2_{m + D}2

r2-r1

_{(ii) Angle of divergence Ф = --- Degrees}

d 2-d1

Where,

N - Number of rulings in the grating (lines/metre) m - Order of the spectrum

Xm - Distance of the mth _{order from Zeroth order (metre)}

D 2 _{- Distance between the laser grating and the screen (metre)}

r1 - Radius of the beam spot at a distance d1 (metre)

r2 - Radius of the beam spot at a distance d 2 (metre)

Procedure:

To the wavelength of the laser source:

The laser source and the laser grating on separate stands as shown in fig. A fixed distance (D) is kept between the laser grating and the screen. The laser source is switched ON and the beam of laser is allowed to fall on the laser grating. The diffracting beams are collected on the screen. The diffracted beams are in the form of sport as shown in fig.

The experiment is repeated for various values of D and the positions of thr spots are noted. Then by using the given formula the wavelength of the laser source can be calculated and the mean is taken.

(ii) To find the angle of a divergence (Ф)

Angle of divergence gives the angular spread of the laser beam. A simple diagrammatic explanation of finding the angle of divergence is shown in fig. 1.5.

Here the laser source and a stand is kept at some distance say d1 and the radius

of the beam spot is measured. Now, by varying the distance to d 2, the radius of the beam

spot is again measured. By substituting these values in the given formula, the angle of divergence can be calculated. The experiment is repeated for various values of d1 and d2

the mean angle of divergence is determined.

To find the wavelength of the laser source (λ

) :

Order

Xm Mean

X2_{m D D}2 _x2_m+D2

λ

LHS RHS Xm

No X10-2_{m X10}-2_{m X10}-2_{m X10}-4_m2 _X10-2_{m X10}-4_m2 _X10-2_{m Ǻ}

First Second

Third Fourth

Fifth Sixth Seventh

Eight

S.No

r

1

d

1

r

2

d

2

r

2

-r

1

Ф =

d

2

-d

1

Unit

X10

-3

m

X10

-2

m

X10

-3

m

X10

-2

m

Degrees

Observation:

(i) Number of rulings in the grating (N) = --- lines/metre (ii) Distance between laser grating and screen (D) =--- X10-2_m

Result:

Aim :

To determine the numerical aperture and acceptance angle of the given optical fiber.

Apparatus Required :

A laser source, scale, optical fiber, numerical aperture measurement jig, etc.

Formula:

1. Numerical aperture of the given optical fiber r

NA = --- No unit r2 _{+ d}2

2. Acceptance angle

0

max = Sin-1NA degree.

Where:

d – Distance between the tip of the optical fiber and the aperture of NA jig. (metre) r – Radius of the circular opening in NA jig (metre)

Procedure:

Measurement of numerical of aperture and acceptance angle:

A known length of fiber is taken. One end of the fiber is connected to laser source and the other end is connected to numerical aperture (NA) jig as shown in the figure. The source is switched ON. The open in the NA jig is completely open so that circular red patch of laser light is observed on the screen. Now the opening in the NA jig is slowly closed with the knob provided, So that at a particular point the circular light patch in the screen just cuts. The radius of the circular opening (r) of NA jig at which the circular patch of light just cuts is measured.

The distance between the NA jig opening and the can the measured directly with the help of the calibration in NA jig. By substituting the values in the given formula the numerical aperture can be calculated.

The same procedure can be adopted for various distance between the fiber and the opening of NA jig. The same procedure can also be adopted for various length of fiber cables.

By finding the mean of numerical aperture (NA) and substituting it in the given formula the acceptance angle can be determined.

S.NO Length of thegiven fiber

Distance between NA jig opening and the

fiber (d)

Radius of the circular opening in numerical aperture

jig ( r )

Numerical aperture r NA =

r2 _{+ d}2

Unit metre X10-2_{m X10}-3_{m No Unit}

Observation :

Result:

1. Numerical aperture of the given optical fiber (NA) = --- No unit 2. Acceptance angle of the given optical fiber (θ) = --- Degree

Aim:

To determine the thermal conductivity of a –bad conductor using Lee’s disc method.

Apparatus Required:

Lee’s disc apparatus, thermometers, steam boiler, stop watch, vernier caliper, Screw gauge, biscuit balance, bad conductor etc.

Formula:

The thermal conductivity of the given bad conductor is MS (dθ/dt) θ2 x (r + 2h)

K = --- Wm-1 _K-1

Πr2 _(θ

1-θ2) 2 (r + h)

Where:

M – Mass of the metallic disc (kg)

S – Specific heat capacity of the material of the disc (JKg-1_K-1₎

Θ1 - Steady state temperature of the steam chamber ˚C

Θ2 - Steady state temperature of the metallic disc ˚C

r - radius of the metallic disc (metre) h - thickness of the metallic disc (metre) X – thickness of the bad conductor (metre)

Procedure:

The experimental arrangement is as shown in the figure. Steam is allowed to pass through the steam chamber. The temperature indicted by two thermometers start rising. After 30 minutes steady state is reached i.e. the temperature of the lower disc is no longer rises. At this stage the temperatures θ1 and θ2 are recorded from the thermometers T1 and

T2.

Now the cupboard is removed and the lower disc is heated by directly by keeping it in contact with steam chamber. When the temperature of the lower disc attains a value 10˚ C more than steady state temperature, the chamber is removed and the lower disc is allowed to cool down.

When the temperature of the disc reaches 5˚ C above the steady state temperature of the disc i.e., ( θ2 + 5 ) ˚C, a stop watch is started and the time is noted for every 1˚C

The thickness and the radius of the metallic disc is found using screw gauge and vernier caliper respectively. Also thickness of the bad conductor is found by screw gauge. The mass of the metallic disc is found by using biscuit balance. The readings are tabulated.

Graph:

A cooling cure graph is drawn by taking time along X-axis and the temperature along Y-axis. The slope of the cooling cure dθ/dt is found and substitutes in the given formula to find conductivity of a bad conductor.

To find (dθ/dt) :

Θ

1

=

θ

2

=

S.No Temperature

˚C

Time (Sec)

To find diameter of the metallic disc:

C.d = ZE = --- X 10-2_m

LC = 0.01 cm ZC = --- X 10-2_m

S.No Main Scale Reading (MSR) Vernier Scale Coincidence (VSC) Vernier Scale Reading VSR =VSC x LC

Observed Reading OR=MSR+VSR

Correct Reading CR=OR±ZC

X 10-2_{m Div X 10}-2_{m X 10}-2_{m X 10}-2_m

Mean 2r =---X 10-2_m

To find the thickness of the card board:

C.d = ZE = --- X 10-3_m

LC = 0.01 mm ZC = --- X 10-3_m

ZE = Cd X LC =

S.No Pitch Scale Reading (PSR) Head Scale Coincidence (HSC) Head Scale Reading HSR = HSC x LC

Observed Reading OR=PSR+HSR Correct Reading CR=OR±ZC

X 10-3_{m Div X 10}-3_{m X 10}-3_{m X 10}-3_m

Mean X = ---X 10-3_m

To find the thickness of the Metallic disc:

C.d = ZE = --- X 10-3_m

LC = 0.01 mm ZC = --- X 10-3_m

S.No

Pitch Scale Reading

(PSR)

Head Scale Coincidence

(HSC)

Head Scale Reading

HSR = HSC x LC

Observed Reading OR=PSR+HSR

Correct Reading CR=OR±ZC

X 10-3_{m Div X 10}-3_{m X 10}-3_{m X 10}-3_m

Mean h = ---X 10-3_m

Observations:

Mass of the metallic disc (M) =--- kg Specific heat capacity of the material of the disc(S) = --- JKg-1_K-1

Steady state temperature of the steam chamber (Θ1) = --- ˚C

Steady state temperature of the metallic disc (Θ2) = --- ˚C

Result:

The thermal conductivity of the conductor = --- Wm-1 _K-1

3. Spectrometer grating –Determination of

Wavelength of the mercury spectrum

To calculate the number of lines per unit length of the given plane transmission grating and to calculate the wavelength of the spectral lines of the mercury spectrum.

Apparatus Required:

Spectrometer, sodium vapour lamp, mercury vapour lamp, plane transmission grating, spirit level etc.,

Procedure:

Preliminary adjustments of the spectrometer are made. The grating is mounted on the grating table. Now set the grating in to normal incidence position.

To determine number of line per grating:

The telescope is moved in to left side,a little away from the direct line. Now first order spectrum of the sodium light is seen. The crosswire is made to coincide with the yellow spectral line. The vernier reading corresponding to this position is noted. Similarly telescope moved to the right side of the direct line and similar readings are taken for the first order spectrum. The difference between these two readings gives 2 Θ. From this we calculate the angle of diffraction Θ. Then the number of lines/meter in the grating is calculate by using the formula.

Sin Ө

N = --- lines/meter nλ

Where,

n - Order of the spectrum

λ - Wavelength of sodium vapour lamp (5893 Ả) Ө - Angle of diffraction (Degree)

To determine the wave length of the spectral:

Without disturbing this spectrometer setup, the sodium vapour lamp is replaced by mercury vapour lamp and now the mercury spectrum is observed through the telescope. As explained before, the telescope is moved to left and right side of the direct ray and the corresponding reading to the prominent spectral lines (like violet, blue, greenish blue, yellow and red) in the first order are noted. The difference between the readings gives 2 Ө and hence of Ө is calculated for the each color.

The wavelength of the spectral line is calculated using the formula given below.

Sin Ө λ = --- Ả

(i)

To find the number of lines per metre of the grating (N):

LC = 1’ (1 minute) Order of the spectrum n = 1

Diffracted ray reading

Vernier – A Vernier - B _R2Ө =

1~ R2 Ө=2Ө/2 Mean

Ө N

MSR VSC TR MSR VSC TR VA VB VA VB

Deg Div Deg Deg Div Deg Deg Deg Deg Deg Deg l/m

Left

Right

Observation:

Order of the spectrum n = Wavelength of sodium vapour lamp λ =--- Ả Angle of diffraction Ө =--- (Degree)

Result:

1. The number of lines/metre in the grating (N) = ---2. Wavelength of various lines of the mercury spectrum are :

4. Ultrasonic interferometer – determination of

Velocity of sound and compressibility of a

Aim:

1. To determination the velocity of ultrasonic waves in the given liquid. 2. To determine the compressibility of the given liquid.

Apparatus Required:

Ultrasonic interferometer, measuring cell, frequency generation, given liquid, etc.,

Formula:

The velocity of the ultrasonic wave in the liquid v = n λ ms-1 Where,

2d

λ = ---- metre x

1

Compressibility of the given liquid k = --- m2_N-1

υ2_ρ Where,

n- Frequency of the generation which exites the crystal (Hertz) λ- Wavelength of ultrasonic (metre)

ρ- Density of the given liquid (kgm-3₎

d- distance moved by the micrometer screw (metre) x – no.of oscillation

Procedure:

The measuring cell is connected to the output terminal of the high frequency generation. This cell is filled with the experimental liquid. Now the frequency generator is switched ON, the ultrasonic waves move normal from the quartz crystal ill they are reflected back by the movable reflector plate. Hence standing waves are formed in the liquid between reflector plate and the quartz crystal.

The distance between reflector and the crystal is varied using the micrometer screw, such that anode current of the generator increases to a maximum and the decreases to a minimum and again increase to maximum. The distance of successive maximum or minimum in the anode current is equal to the half the wavelength of the ultrasonic waves in liquid. So take the readings of the initial and final position of the micrometer screw for one complete oscillation., the distance moved by the deflector can be determined.

After determining the ultrasonic wave velocity in liquid, the compressibility of the liquid is calculated by using the given formula.

(i)To find the velocity of ultrasonic waves in the given liquid:

S.No

No.of Oscillat

ion (X)

Readings for “x” oscillation

d = R1~ R2

2d λ = -

x

velocit y

V=n λ

Initial Reading(R1) Final Reading (R2)

PSR HSC TR PSR HSC TR

x10-3m div x10-3m x 10-3m div x10-3m x 10-3m x 10-3m m/s

Frequency of the generation ‘n’ = 2x106 _HZ

Mean =

1

(ii) Compressibility of the given liquid k = --- m

2

N

-1

υ

2

ρ

Observation:

Frequency of the generation which excites the crucial n =---HZ

Wavelength of ultrasonic λ = ---metre

Distance moved by the micrometer screw d = --- metre

No.of oscillation X =

---Result :

5. Air Wedge – Determination f the thickness of a

thin wire

To determine the thickness of a thin wire by forming interference fringes using an air wedge.

Apparatus Required:

Traveling microscope, two optically plane glass plate, sodium vapour lamp condensing lens, screw gauge, thin wire, etc.,

Formula:

The thickness of the given wire is given by l λ

t = --- metres. 2β

Where,

l = Distance between wire and closed end of the glass plate (metre) t = Thickness of the wire (metre)

β= mean fringe width (metre)

Procedure:

The given wire whose thickness is to be determined is placed at one edge of a pair of optically plane glass plates. Since diameter of the wire is small angle of the wedge is also very small. A sodium vapour lamp is placed at the principal of the condensing lens and hence parallel beam of light is produced. This light is made to fall on a glass plate G held at 45◦ inclination. The reflected light from this glass plate falls normally on the air wedge arrangement. Hence large numbers of equally dark and bright fringes are formed inside the air wedge.

The fine adjustment of the microscope is rotated till the crosswire parallel to the fringes and coincides with one of the dark or bright fringes. Let this is be nth _{fringes. The}

reading in the horizontal vernier scale are noted. This microscope is moved in one direction slowly so that crosswire coincide with (n+5) th _{dark of bright fringes and}

corresponding reading is taken. Similarly reading are noted for (n+10) th _{, (n+15)} th_,(n+20) th _{…….etc fringes. The difference between successive fringes gives width of 5 fringes. So}

mean of this gives fringe width (β). This experiment is repeated by changing distance between the wire and closed end of the glass plate.

To find the band width (β):

Of the fringes

fringes (β)

MSR VSC VSR

=VSCxLC

TR = MSR+VSR

X 10-2m div X 10-2m X 10-2m X 10-2m X 10-2m

n

n+5

n+10

n+15

n+20

n+25

n+30

n+35

n+40

n+45

n+50

LC = 0.001cm

Mean =---m

Observation:

Thickness of the wire t = --- metre

Mean fringe width β = --- metre

Wavelength of the given source (Sodium vapour lamp) λ = --- Ả

Result:

The thickness of the given wire = --- metre.

Aim:

To determine the young’s modulus of the given material of beam by Non-uniform bending.

Apparatus required:

The given beam (metre scale), travelling microscope, weight hangers, pin, slotted weights, screw guage, vernier calipers, knife edges etc.

Formula:

The young’s modulus of the given material of the beam gl3 _M

By calculation Y = --- Nm-2

4bd3 _y

Where:

g - Acceleration due to gravity (ms-2₎

l - Distance between the two knife edges (m) b - Breadth of the beam (m)

d - Thickness of the beam (m)

Y - Elevation produced for ‘M’ kg of load (m) M - load applied (kg)

Procedure:

The given beam is placed over the two knife edges (A and B) at a distance of 70cm (or) 80 cm.

The same procedure is repeated by unloading the weight in steps of same 50 grams and the readings are tabulated in the tabular column. From the readings, the Mean of (M/y) is calculated. The thickness and the breadth of the beam are measured using screw gauge and vernier calipers respectively and are tabulated. By substituting all the values in the given formula, the Young’s Modulus of the given material of the beam can be calculated.

(i)To find the Depression (y):

LC = 0.00l cm TR=MSR+(VSC x LC)

S.No

Distance between

knife edges (l)

Load (M)

Microscope Reading

Mean Depression

(y)

Increasing load Decreasing load

MSR VSC TR MSR VSC TR

unit X 10-2 m kg X 10-2 m Div X 10-2 m X 10-2 m Div X 10-2 m m m

Mean(y) :--- X 10-2 _m

(ii) To find the breath of the beam using vernier calipers:

LC = 0.01 cm ZC = --- X 10-2_m

ZE = Cd X LC

S.No Main Scale Reading (MSR) Vernier Scale Coincidence (VSC) Vernier Scale Reading VSR =VSC x LC

Observed Reading OR=MSR+VSR

Correct Reading CR=OR±ZC

X 10-2_{m Div X 10}-2_{m X 10}-2_{m X 10}-2_m

Mean = ---X 10-2_m

(iii) To find the thickness of the beam using screw gauge (d) :

Cd = ZE = --- X 10-3_m

LC = 0.01 mm ZC = --- X 10-3_m

ZE = Cd X LC

S.No Pitch Scale Reading (PSR) Head Scale Coincidence (HSC) Head Scale Reading HSR = HSC x LC

Observed Reading OR=PSR+HSR Correct Reading CR=OR±ZC

X 10-3_{m Div X 10}-3_{m X 10}-3_{m X 10}-3_m

Mean = ---X 10-3_m

Observation:

Distance between the two knife edges (l) = --- x10-2_m

Breadth of the beam (b) = --- x10-2_m

Thickness of the beam (d) = --- x10-3_m

Elevation produced for ‘M’ kg of load (y) = --- x10-2_m

load applied (M) = --- x10-3_{m (kg)}

Result:

7. Determination of Young’s modulus of the

material – Uniform Bending

Aim:

To determine the young’s modulus of the given material of beam by uniform bending.

Apparatus Required:

The given beam (metre scale), travelling microscope, two weight hangers, pin, slotted weights, screw guage, vernier calipers, knife edges etc.

Formula:

The young’s modulus of the given material of the beam 3gDl2_M

By calculation Y = --- Nm-2

2bd3 _y

Where;

g - Acceleration due to gravity (ms-2₎

D-Distance between the weight hanger and any one of the adjacent knife edge (m) l - Distance between the two knife edges (m)

b - Breadth of the beam (m) d - Thickness of the beam (m)

Y - Elevation produced for ‘M’ kg of load (m) M - load applied (kg)

Procedure:

The given beam is placed over the two knife edges (A and B) at a distance of 70cm (or) 80 cm.

Two weight hangers are suspended, one each on either side of the knife edge at equal distance from the knife edge. A pin is fixed vertically exactly, at the centre of the beam as shown in fig 3.1.

adjusted in such a way that the tip of the pin just touches the horizontal cross-wire. The reading on the vertical scale of the traveling microscope is noted.

Now, equal weights are added on both the weight hangers, in steps of 50 grams. Each time the position of the pin is focused and the readings are noted from the microscope. The procedure is followed until the maximum load is reached.

The same procedure is repeated by unloading the weight from both the weight hangers in steps of same 50 grams and the readings are tabulated in the tabular column. From the readings, the Mean of (M/y) is calculated.

The thickness and the breadth of the beam are measured using screw gauge and vernier calipers respectively and are tabulated. By substituting all the values in the given formula, the Young’s Modulus of the given material of the beam can be calculated.

(i)To find Y

LC = 0.00l cm TR=MSR+(VSC x LC)

S.No

Distance between knife edges

(l)

Load (M)

Microscope Reading

Mean Elevation_(y)

Increasing load Decreasing load

MSR VSC TR MSR VSC TR

unit X 10-2 m kg X 10-2 m Div X 10-2 m X 10-2 m Div X 10-2 m m m

Mean y= ---X 10-2 _m

(ii) To find the breadth of the beam using vernier calipers (b):

LC = 0.01 cm ZC = --- X 10-2_m

ZE = Cd X LC =

S.No Main Scale Reading (MSR) Vernier Scale Coincidence (VSC) Vernier Scale Reading VSR =VSC x LC

Observed Reading OR=MSR+VSR

Correct Reading CR=OR±ZC

X 10-2_{m Div X 10}-2_{m X 10}-2_{m X 10}-2_m

Mean = ---X 10-2_m

(iii) To find the thickness of the beam using screw gauge (d) :

Cd = ZE = --- X 10-3_m

LC = 0.01 mm ZC = --- X 10-3_m

ZE = Cd X LC =

S.No Pitch Scale Reading (PSR) Head Scale Coincidence (HSC) Head Scale Reading HSR = HSC x LC

Observed Reading OR=PSR+HSR Correct Reading CR=OR±ZC

X 10-3_{m Div X 10}-3_{m X 10}-3_{m X 10}-3_m

Mean = ---X 10-3_m

Acceleration due to gravity (g) = --- ms-2

Distance between weight hanger and one of adjacent knife edge (D) = ---x10-2_m

Distance between the two knife edges (l) = --- x10-2_m

Breadth of the beam (b) = --- x10-2_m

Thickness of the beam (d) = --- x10-3_m

Elevation produced for ‘M’ kg of load (y) = --- x10-2_m

load applied (M) = --- x10-3_{m (kg)}

Result:

8. Determination of viscosity of liquid –

Poiseuille’s method.

Aim:

To determine the coefficient of viscosity of the given liquid by poiseeuille’s flow method.

Apparatus Required:

A graduated burette, rubber tube, capillary tube, pinch cock, etc.

Formula:

Л ρ g r4 _ht

Coefficient of viscosity η = --- ---- Nsm-2

8 l V h1 + h2

Driving height of the liquid h = --- - h0 metre.

2

Where:

η – Coefficient of viscosity of the liquid (Nsm-2₎

ρ - Density of the liquid (kg/m3₎

g - Acceleration due to gravity (m/s2₎

r - Radius of the capillary tube (m)

h1 - height from table to initial level of liquid in the burette for a particular range (m)

h2 - height from table to final level of liquid in the burette for a particular range (m)

V - Volume of the liquid (m3₎

h0 - height from table to mid portion of capillary tube (m)

t - Time of flow (Seconds)

l - Length of the capillary tube (m) h – driving height of the liquid (m)

Procedure:

The burette is held vertically on a retort stand. A capillary tube is attached to the lower end of the burette using a rubber tube as shown in fig. The burette is filled with the given liquid. The capillary tube is made horizontal and the liquid is allowed to flow freely through it. When the liquid comes to a known height (h1), which is the height measured

from the axis of the capillary tube, the stop watch is started. The stop watch is stopped when the liquid comes to another level which is of height h2 from the axis of the capillary

tube. Then the driving height is given by h=( h1 + h2) / 2. The driving height, volume of

The experiment is repeated for various known heights of the liquid and the time taken is noted. The mean of (ht/V) is taken. The radius of the bore of the capillary tube fig., can be found by using a traveling microscope by mounting the capillary tube over a stand. Substituting the above data’s in the given formula, the coefficient of viscosity can be calculated.

To find (ht/V)

h0 =

S.No

Volume of

the liquid Time of flow

h1 _h

2

h 1 + h2

h= --- - h0

2 ht/V

Metre3 _{Sec m m m Sec m}-2

Observation:

Coefficient of viscosity of the liquid (η) = --- Nsm-2

Density of the liquid (ρ) = --- kg/m3

Acceleration due to gravity (g) = --- m/s2

Radius of the capillary tube ( r ) = --- m height from table to mid portion of capillary tube (h0) = --- m

Length of the capillary tube (l) = --- m

Result:

(

ii) To find the angle of minimum deviation (D) and refractive index (µ)

LC = 1' Total Reading (TR) = MSR+(VSC x LC)

Angle of prism (A) =

Direct ray Reading

(R

1

) = V

A

=

V

A

=

Position

Vernier - A Vernier - B D =R1~R2

Mean

D Sin (A+D)/2

µ= …………... Sin (A/2)

MSR VSC TR MSR VSC TR VA VB

Deg Deg Deg Deg Deg Deg Deg Deg Deg

Violet-i _{(R2) (R2)}

Violet-ii (R2) (R2)

Blue (R2) (R2)

Blueish

Green (R2) (R2)

Green (R2) (R2)

Yellow-i (R2) (R2)

Red (R2) (R2)

Result:

(i) The refractive index of the material of the given prism (µ) =…………..degrees (ii) Mean dispersive power of the prism =…………..degrees

(iii) Measurement of the diameter of the disc using vernier calipers:

LC = 0.01 cm ZC = --- X 10-2_m

ZE = Cd X LC

S.No

Main Scale Reading

(MSR)

Vernier Scale Coincidence

(VSC)

Vernier Scale Reading

VSR =VSC x LC

Observed Reading OR=MSR+VSR

Correct Reading CR=OR±ZC

X 10-2_{m Div X 10}-2_{m X 10}-2_{m X 10}-2_m

Mean = ---X 10-2_m

Result:

(i) The moment of inertia of the disc ( I ) = --- Kgm 2

(ii) The rigidity modulus of the suspension wire (n) (a) By calculation = --- Nm-2

(b) By graph = --- Nm-2