e-book 2022

Physics Practicals BSPH 402

Prof. K S Kahlon Mr Manjodh Singh Banga Ms Shakun Pandey

Volume 1

Sant Longowal Institute of Engineering and Technology, Longowal 148106 DEEMED TO BE UNIVERSITY

Acknowledgement THANKS FOR SUPPORT AND ENCOURAGEMENT PROF. SHAILENDRA JAIN

PROF. J S DHILLON PROF. HARISH K CHOPRA PROF. A S DHALIWAL PROF. M M SINHA

PROF. S S VERMA

.

1

Determination of the https://youtu.be/ 6 3DI86zX735U value of e/m of an electron by Helical method

Use of Michelson Interferometer for determining the wavelength of He-Ne laser

2

To find wavelength of He https://youtu.be/ 7 Ne laser using diffraction 4iRCTu7LH8A grating

Measurement of Numerical https://youtu.be/hy4vngL Aperture of Optical Fibre pFxE

3

To verify inverse square https://youtu.be/ 8 law of radiation using a jaKXXNWiQP0 photo-electric effect

Evaluate phase difference between two sinusoidal https://youtu.be/YJTdM3jT signals applied to X and Y EKo inputs of cathode day oscilloscope

4

Experiment to determine https://youtu.be/ 9 frequency of unknown lFxn_ZO-cu0 signal by drawing Lissajous patterns

5

To Determine Frequency https://youtu.be/ 10 Of AC mains By ZnXKRpC9aX0 Electrically Maintained Tuning Fork

To find the value of Planck’s https://youtu.be/0o1G8qN constant and photo electric work tTYk function of the material of the cathode using a photo-electric cell To find the frequency of the given https://youtu.be/QvWH3h Au-zA tuning fork using a Sonometer

https://youtu.be/jQEpKznj tI0

Determination of the value of e/m of an electron by Helical method Video link

https://youtu.be/3DI86zX735U

e/m ratio (or specific charge) 𝟐 +𝑳𝟐 ) 𝑽 𝒆 (𝑫 = 𝟓 𝑿 𝟏𝟎𝟏𝟑 𝟐 𝟐 𝟐 𝒎 𝑵 𝒍𝒙 𝑰

(Not used) For measuring deflection voltage

Length of line can be changed to spot by increasing current

Select X or Y Plate

Ammeter

Vary acceleration voltage

Voltmeter

Reverse the solenoid current

Length of line for X plate can be changed

Power supply solenoid

Length of line for Y plate can be changed

Power supply to CRT

Focus of line can be adjusted Adjusting brightness of line

Least Count 0.02A

Least Count 20 V

Solenoid and CRT connected to Power supply

S N

Video showing connections for Solenoid and CRT to power supply

1. Current to zero from fine knob

2.

Select X plate

3. Voltage at 640 V selection from

4.

From X shift length of line on CRT will be changed to 3 cm

5)

intensity and Focus of line

6)

From fine (current) make line to spot on CRT

7)

Note current reading

8)

Note reading of current at reverse also.

9)

Repeat at 700V and 760V also.

Above procedure can be repeated for Y plate also.

Video press Below

X plate

𝑽 𝑰𝟐

𝟐 + 𝑳𝟐 ) 𝑽 𝒆 (𝑫 = 𝟓 𝑿 𝟏𝟎𝟏𝟑 𝒎 𝑵𝟐 𝒍 𝒙 𝟐 𝑰𝟐

𝒆 = 𝟏. 𝟖𝑿𝟏𝟎𝟏𝟏 𝒎 𝒆 = 𝟏. 𝟖 𝑿𝟏𝟎𝟏𝟏 𝒎 𝒆 = 𝟏. 𝟖𝑿𝟏𝟎𝟏𝟏 𝒎

Voltage

Current

Reverse Current

Average

640 V

0.58 A

0.58 A

0.58 A

1902.5

700 V

0.60 A

0.60 A

0.60A

1944

760 V

0.64 A

0.64 A

0.64 A

2800

2 2 𝑒 (𝐷 + 𝐿 )𝑉 13 = 5 𝑋 10 𝑚 𝑁 2 𝑙𝑥 2 𝐼 2

𝐿 𝑖𝑠 𝑡ℎ𝑒 𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑆𝑜𝑙𝑒𝑛𝑜𝑖𝑑 = 44𝑋10−2 𝑚 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑢𝑟𝑛𝑠 𝑁 = 3000 turns Distance of x plate from screen 𝑙𝑥 = 0.11𝑚 𝐷 𝑖𝑠 𝑡ℎ𝑒 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑆𝑜𝑙𝑒𝑛𝑜𝑖𝑑 = 10.5𝑋10−2 𝑚 𝑭𝒐𝒓 𝒙 𝒑𝒍𝒂𝒕𝒆 (𝐷 2 +𝐿2 )= 110.25𝑋10−4 + 1936𝑋10−4 = 10−4 𝑋2046.25 𝑁 2 𝑙𝑥 2 = 9𝑋106 𝑋0.0121 = 0.1089𝑋106 (𝐷2 +𝐿2 ) −6 2 =1.8790𝑋10 2 𝑁 𝑙𝑥 2 2 2 2 (𝐷 +𝐿 ) 13 13 (𝐷 +𝐿 ) = 5 𝑋 10 𝑋 2 2 =9.5X107 2 𝑋5 𝑋 10 2 𝑁 𝑙𝑥 𝑁 𝑙𝑥 2 + 𝐿2 ) 𝑉 𝑒 (𝐷 𝑉 13 7 = 5 𝑋 10 2 𝐼 2 = 9.5X10 𝑋 𝐼 2 2 𝑚 𝑁 𝑙𝑥 𝑒 = 1.8𝑋1011 C/kg 𝑚 𝑒 𝑉 = 1.8𝑋1011 C/kg 𝑚 𝑒 𝑉 = 1.8𝑋1011 C/kg 𝑚

1) 𝐹𝑜𝑟 640 𝑉 2) 𝐹𝑜𝑟 700 3) 𝐹𝑜𝑟 760

𝒆 𝑺𝒕𝒂𝒏𝒅𝒂𝒓𝒅 𝑽𝒂𝒍𝒖𝒆 = 𝟏. 𝟕𝑿𝟏𝟎𝟏𝟏 𝒎 𝑴𝒆𝒂𝒔𝒖𝒓𝒆𝒅 𝑽𝒂𝒍𝒖𝒆 − 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 = 𝑿𝟏𝟎𝟎 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆 𝟏. 𝟖𝑿𝟏𝟎𝟏𝟏 − 𝟏. 𝟕𝑿𝟏𝟎𝟏𝟏 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 = 𝑿𝟏𝟎𝟎 = 𝟓% 𝟏𝟏 𝟏. 𝟕𝑿𝟏𝟎 Above procedure can be repeated for Y plate also.

To find wavelength of He Ne laser using diffraction grating https://youtu.be/4iRCTu7LH8A

1. Grating is fixed below in the instrument below microscope. 1 2. Least count of circular scale =0.001Cm =(100)𝑚𝑚 0.001

3. Least of this scale = 10 Cm=0.0001Cm 4. Point 2 works like screw gauge and point 3 like Vernier calliper. 5. Arrow for point 2 is circular scale.

1. Distance between first two arrows combination of transparent and opaque slit of grating , that is grating element.From first to third arrows are ten slits. 2. We first put crosswire at first arrow on the grating and take the reading. 3. Move the circular scale in particular direction so that we crossed the slits and reached at third arrow.

1. When cross wire at first arrow 2. Upper zero position is noted 3. It is 2mm complete and 3mm is not complete.

1. On circular scale 79 th division is complete. 2. On third scale 7th line is matching exactly. 3. So starting reading will be 4. 0.2cm + 79X0.001cm +7x0.0001Cm 5. = 0.2 + 0.079 + 0.0007 =0.2797cm 6. This above is starting reading means arrow at a first position

1. Move the drum (circular scale in such a direction that cross wire on third arrow position 2. Reading is 5mm (complete)

1. On circular scale 13 th division is complete. 2. On third scale 7th line is matching exactly. 3. So above reading will be 0.5cm + 13X0.001cm +7x0.0001Cm = 0.5 + 0.013 + 0.0007 =0.5137cm This above is final reading means arrow at tenth position . 4. Final reading – initial reading = 0.5137 cm - 0.2797 cm = 0.234 Cm 5. The above is for ten slits combination (opaque and transparent) 0.234 6. d= cm=0.0234cm 10

𝑃0 𝑡𝑜 𝑄

𝑃0 𝑡𝑜 𝑃1

sin 𝜃 =

𝑃1 𝑃0 𝑃1 𝑃0 2 + 𝑄𝑃0 2

1.5 cm sinθ = = 0.003 500.002 cm sinθ λ= (a + b) n Where n =1 and a + b = 0.0234 cm 0.003 λ= 0.0234 = 0.0000702 cm = 702 nm 1 He-Ne wavelength actual value = 632.8 nm

Percentage error =

702−632.8 632.8

× 100 = 10.9 %

https://youtu.be/jaKXXNWiQP0

To verify inverse square law of radiation using a photo-electric effect 𝑰(𝒊𝒏𝒕𝒆𝒏𝒔𝒊𝒕𝒚 𝒊𝒏 𝒕𝒆𝒓𝒎𝒔 𝒐𝒇 𝒄𝒖𝒓𝒓𝒆𝒏𝒕)′𝜽′ ′𝜽′ I∝

CAUTION

𝟏 𝒓𝟐

Reading depend on light intensity and can not be repeated

Photo cell inside (A)

Filter Lamp

Selection of Current value after decimal

Can be used as voltmeter or ammeter by sliding knob

Photo cell

Light intensity of lamp can be changed

Voltage to anode of photo cell Voltage can be changed from negative to positive (by sliding knob)

Example 𝑪𝒖𝒓𝒓𝒆𝒏𝒕 𝒎𝒖𝒍𝒕𝒊𝒑𝒍𝒊𝒆𝒓 Current value (Example) 𝒔𝒆𝒍𝒆𝒄𝒕𝒊𝒐𝒏

𝑋1

5 μ𝐴

𝑋0.1

5.1 μ𝐴

𝑋0.01

5.12 μ𝐴

𝑋0.001

5.123 μ𝐴

Photocell (A)

Step 1 Keep the voltage [positive] constant Select the multiplier between X0.1 to X0.001 Step 2 Position of the photo-cell is fixed Step 3 Intensity of lamp should be fixed Step 4 Decrease the distance of the mercury lamp from the photo-cell in small steps Step 5 Slide the knob towards current (𝝁𝑨) for measuring intensity ′𝜽′

Video [Press below]

Distance between lamp and 𝟏 −𝟐 𝑖𝑛 𝒄𝒎 photo cell ‘r’ 𝒓𝟐

Filter Colour Red ( 𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒊𝒏 𝝁𝑨)

Filter Colour green (𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒊𝒏 𝝁𝑨)

′𝜽′

′𝜽′

40 𝑐𝑚

0.00063

1.17

10.12

35 𝑐𝑚

0.00082

1.56

13.41

30 𝑐𝑚

0.0011

2.30

14.65

25 𝑐𝑚

0.0016

3.48

18.54

20 𝑐𝑚

0.0025

5.53

25.43

30

5

Red colour filter

Green colour filter

4.5 25 4 3.5

20

3

θ

15

2.5 2

θ

1.5 1

10

5

0.5 0

0 0

5

10

15

20

25

30

0

1/𝑟^2

5

10

15

1/𝑟^2

Graph between intensity and 1/square of distance

1 𝑟2

is almost straight line

20

25

30

Experiment to determine frequency of unknown signal by drawing Lissajous patterns https://youtu.be/lFxn_ZO-cu0

Function Generator 1 FUNCTION

Waveform selection

2 Range

Frequency range selection

3 Hz/kHz

Frequency in Hz and kHz.

4 FREQEN

Frequency adjustment

5 COUNTER

Signal input terminal for Frequency counter

6 FINE

Frequency fine tune (output signal) 3 2 3 6

4

5 Power

1

7

COUNTER INT/EXT

Signal attenuator (Internal/External)

8

MOD

EXT/INT modulation selection, Internal and External selection

9

CMOS LEVEL

Adjust CMOS level (pull) [Complementary Metal Oxide Semiconductor(CMOS)]

10

ATT

Attenuator

11

DC

DC output can be adjusted (pull out knob)

12

OUTPUT

Signal output

13

AMPL/INV

Amplification and Inversion of waveform (pulling out knob)

14

TTL/CMOS

Output TTL/CMOS pulse can be used [Transistor-Transistor Logic(TTL)]

15

SYM

Symmetry and ramp of pulse can be adjusted

16

VCF IN

Frequency control by external voltage input (VCF input)

Function Generator 9

13

11

7/8

15

14

10

12

16

Oscilloscope

9

8

2

3

4

10

10 12

7

1

9 8

11

5

6

1 2 3 4 5

POWER

8

SELECT THE VERTICAL AXIS SENSITIVITY Amplitude)

INTENSITY ADJUSTMENT FOCUS CAN BE ADJUSTED TRACE ROTATION CH1(X) X AXIS INPUT TERMINAL

9

FINE ADJUSTMENT OF SENSITIVITY CH1 and CH2

10

↕ POSITION CONTROL

11

6

CH2 (Y) Y AXIS INPUT TERMINAL

7

AC GND DC (SWITCH FOR SELECTING CONNECTION MODE ) AC: AC COUPLING. GND:AMPLIFIER INPUT IS GROUNDED DC: DC COUPLING 12

MODE CH 1: CH1 OPERATION ONLY CH 2: CH2 OPERATION ONLY DUAL : CH1 AND CH2 OPERATIONS TOGETHER ADD : DISPLAYS CH1 AND CH2

VERTICAL POSITIONING

ALT/CHOP IN THE DUAL TRACE MODE THE CH1 AND CH2

18 24

19

20

17

21

16

1

CH2 INV : INVERTS THE CH2 INPUT SIGNAL

14

TRIG IN :INPUT TERMINAL IS USED FOR EXTERNAL TRIGGERING SIGNAL

15

SOURCE:SELECT THE INTERNAL TRIGGERING SOURCE SIGNAL

16

SLOPE:SELECT THE TRIGGERING SLOPE

17

LEVEL: SET A START POINT FOR THE WAVEFORM

18

TRIGGER MODESELECT: THE DESIRED TRINGGER MODE BETWEEN AUTO, NORM, TV-V AND TV-H

14

13

23

13

15

22

19

TIME/DIV : SWEEP TIME RANGES PER DIVISION

20

SWP VAR: FINE CONTROL FOR TIME/DIV

21

X10 MAG: MAGNIFICATION OF SIGNAL

22

GND: GROUND TERMINAL OF OSCILLISCOPE

23

CAL:DELIVERS CALIBRATION VOLTAGE

24

Wave or line displacement in horizontal direction

Experiment

Function Generator CRO

Following are settings for experiment 1 Power on 2 Select XY 3 Signal from two function generators

1. Take out wire from channel 2 2. Select length of line (say four centimetres) on oscilloscope from point 8,9 (left side) (on oscilloscope) 13 (function generator) and position of line on point 24 ( on oscilloscope). 3. Intensity and focus of line can be changed from 2 and 3. of channel 2 and take out 4. Put wire wire from channel 1. 5. Select length of line (say four centimetres) on oscilloscope from point 8,9 (right side) (on oscilloscope) 13 (function generator) and position of line on point 10 ( on oscilloscope).

24

13

XY

VIDEO

VIDEO

Lissajous figures Frequency ratios of two sinusoidal Shape of Patterns signals 1:1 2:1

1:2 1:3

To find the frequency of the given tuning fork using a Sonometer Frequency =

𝟏 n= 𝟐𝒍

𝑻 𝒎

https://youtu.be/QvWH3hAu-zA

Sonometer

Two bridges

Tuning fork

Weight hanger Rubbers of two types for striking of Tuning fork

Tuning fork will be hit on rubber and placed between two bridges. Paper on wire will not fall. Now we will increase the distance between bridges and again Tuning fork will be hit on rubber and placed between two bridges. We will find the position of bridges, where Paper (rider) on wire will fall {Increasing is written in table).

Tuning fork will be hit on rubber and placed between two bridges. Paper on wire will not fall. Now we will decrease the distance between bridges and again Tuning fork will be hit on rubber and placed between two bridges. We will find the position of bridges, where Paper(rider) on wire will fall {decreasing is written in table).

Video

Video

Press with computer mouse here

m = 1.22 gram/meter = 0.0122 gram/cm (given) Weight=M

T= Mg

1000 gram

980000

1500 gram

1470000

𝑔 −𝑐𝑚 𝑠𝑒𝑐 2 𝑔 −𝑐𝑚 𝑠𝑒𝑐 2

𝒍𝟏 +𝒍𝟐 𝟐

Increasing 𝒍𝟏

Decreasing 𝒍𝟐

24 cm

24 cm

24 cm

1 2 𝑋 24

30 cm

30 cm

30 cm

1 2 𝑋 30

Average =

Average =

Frequency =

𝐼𝑠𝑡 𝑟𝑒𝑎𝑑𝑖𝑛𝑔+2𝑛𝑑 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 2

187 + 183 = = 185 ℎ𝑒𝑟𝑡𝑧 2

Actual value=256 hertz (given on tuning fork) Experimental Value =185 hertz Error=

𝑻𝒉𝒆𝒐𝒓𝒆𝒕𝒊𝒄𝒂𝒍 𝒗𝒂𝒍𝒖𝒆 −𝒆𝒙𝒑𝒆𝒓𝒊𝒎𝒆𝒏𝒕𝒂𝒍 𝒗𝒍𝒖𝒆 𝑋 𝒆𝒙𝒑𝒆𝒓𝒊𝒎𝒆𝒏𝒕𝒂𝒍 𝒗𝒂𝒍𝒖𝒆

100 =

256−185 X100= 185

38%

1 n= 2𝑙

𝑇 𝑚

980000

0.0122 = 187 hertz 1470000

0.0122 = 183 hertz

Use of Michelson Interferometer for determining the wavelength of He-Ne laser Wavelength=

2𝑋𝑑 𝑚

https://youtu.be/jQEpKznjtI0

A

B

C

D

1 Give one complete rotation to wheel C. 2 Hundred division will move on scale B. 3 It will move one division on scale A. 1 Give one complete rotation to wheel E. 2 Hundred division will move on scale D 3 It will move one division on scale B.

E

𝟏𝒅𝒊𝒗𝒊𝒔𝒊𝒐𝒏 𝒐𝒏 𝒔𝒄𝒂𝒍𝒆 𝑨 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑩 = 𝟏𝟎𝟎 𝒅𝒊𝒗𝒊𝒔𝒊𝒐𝒏𝒔 𝒐𝒏 𝒔𝒄𝒂𝒍𝒆 𝑩 𝟏𝒎𝒎 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑩 = = 𝟎. 𝟎𝟏𝒎𝒎 𝟏𝟎𝟎 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑩= One division distance of scale B

B

B

𝟏𝒅𝒊𝒗𝒊𝒔𝒊𝒐𝒏 𝒐𝒏 𝒔𝒄𝒂𝒍𝒆 𝑩 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑫 = 𝟏𝟎𝟎 𝒅𝒊𝒗𝒊𝒔𝒊𝒐𝒏𝒔 𝒐𝒏 𝒔𝒄𝒂𝒍𝒆 𝑫 𝟎. 𝟎𝟏𝒎𝒎 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑫 = = 𝟎. 𝟎𝟎𝟎𝟏𝒎𝒎 𝟏𝟎𝟎 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑫= One division distance of scale D

D

A

D

B

Reading (Example)

Least Count of scale B=0.01mm Least Count of scale D=0.0001mm Reading = 𝟏𝒎𝒎 + 𝟐𝟔𝑿𝟎. 𝟎𝟏𝒎𝒎 + 𝟖𝟑𝑿𝟎. 𝟎𝟎𝟎𝟏𝒎𝒎

𝑹𝒆𝒂𝒅𝒊𝒏𝒈 = 𝟏. 𝟐𝟔𝟖𝟑𝒎𝒎

Beam splitters Movable mirror Half silvered glass plate

Compensatory Glass plate Screws at back of two mirrors

Fixed mirror

𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑫 =

Screen

A

B

𝟎. 𝟎𝟏𝒎𝒎 = 𝟎. 𝟎𝟎𝟎𝟏𝒎𝒎 𝟏𝟎𝟎

𝟏𝒎𝒎 𝑳𝒆𝒂𝒔𝒕 𝑪𝒐𝒖𝒏𝒕 𝒐𝒇 𝒔𝒄𝒂𝒍𝒆 𝑩 = = 𝟎. 𝟎𝟏𝒎𝒎 𝟏𝟎𝟎

D

Three scales

He Ne laser

Match these two spots by using screws behind mirrors Without beam splitters

Put beam splitters in place after matching the spots we will see fringes on screen

Fringes

Video press below

‘B’ Reading between 18 and 19 ‘D’ Reading at 98

‘A’ Reading at 0

Initial reading=0+18X0.01+98X0.0001=0.1898mm 𝟎. 𝟎

Reading at 0

Reading between 19 and 20

Reading at 40

Final reading(After shifting twenty fringes) =0+19X0.01+40X0.0001=0.1941mm

S Initial reading No.

1

Final reading

Final reading-Initial reading

0+18X0.01+98X0.0001 0+19X0.01+41X0.0001 0.1941mm-0.1898=0.0043 =0.1898mm =0.1941mm

Wavelength=

2𝑋

Final reading−Initial reading 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑓𝑟𝑖𝑛𝑔𝑒𝑠 𝑠ℎ𝑖𝑓𝑡𝑒𝑑

2𝑋0.0043 0.0086 Wavelength= = = 0.00043𝑚𝑚 = 430𝑛𝑚 20 20

𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑓𝑟𝑖𝑛𝑔𝑒𝑠 𝑠ℎ𝑖𝑓𝑡𝑒𝑑 20

2𝑋0.0043 𝑴𝒆𝒂𝒔𝒖𝒓𝒆𝒅 Wavelength= = 430𝑛𝑚 20

𝑴𝒆𝒂𝒔𝒖𝒓𝒆𝒅 𝑽𝒂𝒍𝒖𝒆 − 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 = 𝑿𝟏𝟎𝟎 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆 𝟒𝟑𝟎 − 𝟔𝟑𝟐 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 = 𝑿𝟏𝟎𝟎 = 𝟑𝟐% 𝟔𝟑𝟐

Measurement of Numerical Aperture of Optical Fibre https://youtu.be/hy4vngLpFxE

Numerical aperture( NA) is the efficiency with which light is collected inside the optical fiber in order to get propagated. Light through an optical fiber is propagated through total internal reflection.

He Ne laser Screen

Scale used to measure distance Fibre wire

1. Distance between optical fibre and screen is varied

2. Diameter of only bright red portion is measured on this screen

Diameter of bright red portion is noted

Distance between screen optical fibre is noted from here.

Video Press below (on triangle)

S . No.

𝑫 𝟐𝒁

𝑫 𝟐𝒛

𝑵𝑨 = sin 𝜽

Diameter of Laser Spot (𝑫𝒄𝒎 ) (only bright portion is measured)

Distance between optical fibre and screen (𝒁𝒄𝒎 )

1

1.6

12

0.13

7.410

0.129

2

1.9

16

0.12

6.840

0.119

3

2.1

20

0.11

6.280

0.109

For all calculations calculator is on degree mode

−𝟏

𝜽 = 𝒕𝒂𝒏

NA(Numerical Apperture) =

0.129 + 0.119 + 0.109 = 0.119 3

Evaluate phase difference between two sinusoidal signals applied to X and Y inputs of cathode day oscilloscope https://youtu.be/YJTdM3jTEKo

Function Generator 1 FUNCTION

Waveform selection

2 Range

Frequency range selection

3 Hz/kHz

Frequency in Hz and kHz.

4 FREQEN

Frequency adjustment

5 COUNTER

Signal input terminal for Frequency counter

6 FINE

Frequency fine tune (output signal) 3 2 3 6

4

5 Power

1

7

COUNTER INT/EXT

Signal attenuator (Internal/External)

8

MOD

EXT/INT modulation selection, Internal and External selection

9

CMOS LEVEL

Adjust CMOS level (pull) [Complementary Metal Oxide Semiconductor(CMOS)]

10

ATT

Attenuator

11

DC

DC output can be adjusted (pull out knob)

12

OUTPUT

Signal output

13

AMPL/INV

Amplification and Inversion of waveform (pulling out knob)

14

TTL/CMOS

Output TTL/CMOS pulse can be used [Transistor-Transistor Logic(TTL)]

15

SYM

Symmetry and ramp of pulse can be adjusted

16

VCF IN

Frequency control by external voltage input (VCF input)

Function Generator 9

13

11

7/8

15

14

10

12

16

Oscilloscope

9

8

2

3

4

10

10 12

7

1

9 8

11

5

6

1 2 3 4 5

POWER

8

SELECT THE VERTICAL AXIS SENSITIVITY Amplitude)

INTENSITY ADJUSTMENT FOCUS CAN BE ADJUSTED TRACE ROTATION CH1(X) X AXIS INPUT TERMINAL

9

FINE ADJUSTMENT OF SENSITIVITY CH1 and CH2

10

↕ POSITION CONTROL

11

6

CH2 (Y) Y AXIS INPUT TERMINAL

7

AC GND DC (SWITCH FOR SELECTING CONNECTION MODE ) AC: AC COUPLING. GND:AMPLIFIER INPUT IS GROUNDED DC: DC COUPLING 12

MODE CH 1: CH1 OPERATION ONLY CH 2: CH2 OPERATION ONLY DUAL : CH1 AND CH2 OPERATIONS TOGETHER ADD : DISPLAYS CH1 AND CH2

VERTICAL POSITIONING

ALT/CHOP IN THE DUAL TRACE MODE THE CH1 AND CH2

18 24

19

20

17

21

16

1

CH2 INV : INVERTS THE CH2 INPUT SIGNAL

14

TRIG IN :INPUT TERMINAL IS USED FOR EXTERNAL TRIGGERING SIGNAL

15

SOURCE:SELECT THE INTERNAL TRIGGERING SOURCE SIGNAL

16

SLOPE:SELECT THE TRIGGERING SLOPE

17

LEVEL: SET A START POINT FOR THE WAVEFORM

18

TRIGGER MODESELECT: THE DESIRED TRINGGER MODE BETWEEN AUTO, NORM, TV-V AND TV-H

14

13

23

13

15

22

19

TIME/DIV : SWEEP TIME RANGES PER DIVISION

20

SWP VAR: FINE CONTROL FOR TIME/DIV

21

X10 MAG: MAGNIFICATION OF SIGNAL

22

GND: GROUND TERMINAL OF OSCILLISCOPE

23

CAL:DELIVERS CALIBRATION VOLTAGE

24

Wave or line displacement in horizontal direction

Function Generator

CRO

Signal to CRO at Channel 1 of CRO

𝑃ℎ𝑎𝑠𝑒 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑒𝑥𝑝𝑒𝑟𝑚𝑒𝑛𝑡𝑎𝑙 𝑋1 −1 𝜑 = sin 𝑋2

𝑋1 𝑋2

Frequency = 285 Hz

S No

1

𝑹

𝑪

20𝑘Ω

104 𝑝𝐹

𝑿𝟏

𝑿𝟐

Phase difference

𝛗 = 𝐬𝐢𝐧−𝟏

𝑿𝟏 𝑿𝟐

20 mm 30mm

𝜑 = sin−1

20 = 410 30

(103 DISC)

2

68kΩ

104 𝑝𝐹

18mm 26mm

𝜑=

sin−1

18 = 440 26

3

200kΩ 104 𝑝𝐹

10mm 20mm

𝜑 = sin−1

10 = 300 20

https://youtu.be/0o1G8qNtTYk

To find the value of Planck’s constant and photo electric work function of the material of the cathode using a photo-electric cell PLANKS CONSTANT= 𝒆𝒕𝒂𝒏𝜽 = 𝒆

∆𝑽 𝒔 ∆𝝑

WORK FUNCTION = 𝒉𝒗 𝟎 CAUTION

READING DEPEND ON LIGHT INTENSITY AND CAN NOT BE RE PEATED

Photocell inside (A)

Filter Lamp

Selection of Current value after decimal

Can be used as voltmeter or ammeter by sliding knob

Photo cell

Light intensity of lamp can be changed

Voltage to anode of photocell

Voltage can be changed from negative to positive (by sliding knob)

Example 𝑪𝒖𝒓𝒓𝒆𝒏𝒕 𝒎𝒖𝒍𝒕𝒊𝒑𝒍𝒊𝒆𝒓 Current value (Example) 𝒔𝒆𝒍𝒆𝒄𝒕𝒊𝒐𝒏

𝑋1

5 μ𝐴

𝑋0.1

5.1 μ𝐴

𝑋0.01

5.12 μ𝐴

𝑋0.001

5.123 μ𝐴

Photocell (A)

Step 1 Step 2 Step 3 Step 4

Step 1 Step 2 Step 3 Step 3 Step 4

Position of the photo-cell is fixed 𝐒𝐞𝐥𝐞𝐜𝐭 𝐭𝐡𝐞 𝐦𝐮𝐥𝐭𝐢𝐩𝐥𝐢𝐞𝐫 𝐚𝐭 𝐗𝟎. 𝟎𝟎𝟏 Intensity of lamp should be fixed Keep the voltage direction [negative]

Set display mode to current and rotate the knob of voltage adjustor so that current is zero Shift display mode to voltage Don't touch voltage adjustor and note down corresponding reading. stopping potential 𝑽𝒔 Above is repeated for different filters 𝑾𝒊𝒕𝒉 𝒔𝒂𝒎𝒆 𝒔𝒆𝒕𝒕𝒊𝒏𝒈𝒔 Plot a graph between stopping potential 𝑽𝒔 and corresponding frequency ‘’ [filter]

Video

Filter

Green color

Wavelength

𝟓𝟐𝟎𝑿𝟏𝟎−𝟗 𝒎

Frequency (𝒔𝒆𝒄−𝟏 ) 𝒄 𝝑 = 𝜸

𝟎. 𝟎𝟎𝟓𝟕𝟕 𝑿𝟏𝟎𝟏𝟕



Stopping Potential 𝑽𝒔

𝟎. 𝟕𝟑 𝑽 (magnitude)

Dark Yellow color 𝟓𝟓𝟎𝑿𝟏𝟎−𝟗 𝒎

Red color 𝟔𝟑𝟎𝑿𝟏𝟎−𝟗 𝒎

Blue color

𝟒𝟕𝟎𝑿𝟏𝟎−𝟗 𝒎

𝟎. 𝟎𝟎𝟓𝟒𝟓 𝑿𝟏𝟎𝟏𝟕 𝟎. 𝟎𝟎𝟒𝟕𝟔 𝑿𝟏𝟎𝟏𝟕 𝟎. 𝟎𝟎𝟔𝟑𝟖𝑿𝟏𝟎𝟏𝟕

𝟎. 𝟓𝟑 𝑽

𝟎. 𝟐𝟏𝑽

𝟏. 𝟎𝟔 𝑽

Orange Color

𝟓𝟖𝟎𝑿𝟏𝟎−𝟗 𝒎

𝟎. 𝟎𝟎𝟓𝟏𝟕 𝑿𝟏𝟎𝟏𝟕

𝟎. 𝟑𝟔 𝑽

Plot a graph between stopping potential 𝑽𝒔 ( Y-axis) and corresponding frequency  (X-axis). Graph is a straight line

Stopping Potential

Line intersecting on x axis is Threshold frequency

Slope = 539 × 10−17

Frequency𝑋1017 e= 1.6 × 10−19 𝐶𝑜𝑢𝑙𝑚𝑏

𝐴𝑐𝑡𝑢𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 = 6.62 × 10−34 𝑗𝑜𝑢𝑙𝑒𝑠 𝑠𝑒𝑐

∆𝑉

h= 𝑒𝑡𝑎𝑛𝜃 = 𝑒 ∆𝜗𝑠 = 𝑒 [ 𝑠𝑙𝑜𝑝𝑒]

𝑴𝒆𝒂𝒔𝒖𝒓𝒆𝒅 𝒗𝒂𝒍𝒖𝒆 𝒉 = 𝟖. 𝟔𝟐 × 𝟏𝟎−𝟑𝟒 𝑱𝒐𝒖𝒍𝒆𝒔 − 𝒔𝒆𝒄

𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 =

𝑴𝒆𝒂𝒔𝒖𝒓𝒆𝒅 𝑽𝒂𝒍𝒖𝒆 − 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆 𝑿𝟏𝟎𝟎 𝑬𝒙𝒂𝒄𝒕 𝑽𝒂𝒍𝒖𝒆

𝟖. 𝟔𝟐𝑿𝟏𝟎−𝟑𝟒 − 𝟔. 𝟔𝑿𝟏𝟎−𝟑𝟒 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝑬𝒓𝒓𝒐𝒓 = 𝑿𝟏𝟎𝟎 = 𝟑𝟎% 𝟔. 𝟔𝑿𝟏𝟎−𝟑𝟒 𝟏 𝑱𝒐𝒖𝒍𝒆 = 𝟔. 𝟐𝟒 × 𝟏𝟎𝟏𝟖 𝒆𝑽 𝑾𝒐𝒓𝒌𝒇𝒖𝒏𝒄𝒕𝒊𝒐𝒏 = 𝑻𝒉𝒓𝒆𝒔𝒉𝒐𝒍𝒅 𝒇𝒓𝒆𝒒𝒖𝒆𝒏𝒄𝒚 𝑿 𝒉 𝑾𝒐𝒓𝒌𝒇𝒖𝒏𝒄𝒕𝒊𝒐𝒏 = 𝟖. 𝟔𝟐𝑿𝟏𝟎−𝟑𝟒 𝑿𝟎. 𝟎𝟎𝟒𝟒𝑿𝟏𝟎𝟏𝟕 𝑱𝒐𝒖𝒍𝒆𝒔 𝑾𝒐𝒓𝒌𝒇𝒖𝒏𝒄𝒕𝒊𝒐𝒏 = 𝟎. 𝟎𝟑𝟗𝟕𝑿𝟏𝟎−𝟏𝟕 𝑱𝒐𝒖𝒍𝒆𝒔 𝑾𝒐𝒓𝒌 𝒇𝒖𝒏𝒄𝒕𝒊𝒐𝒏 = 𝟐. 𝟒𝟖 𝒆𝑽

To Determine Frequency Of AC mains By Electrically Maintained Tuning Fork Melde’s Experiment https://youtu.be/ZnXKRpC9aX0

Thread

Electrically Maintained Tuning fork Transverse mode

Vibrator

Setting of Loops from here

Meldes Method

The size of loop ( if fraction is there) can be changed by changing this distance between electromagnet and pulley.( By dragging electromagnet). Pulley

Pan

Loops

Video ( Move the Computer Mouse BELOW To see video)

Mass in pan (𝑀)

Total Tension 𝑇 = (𝒑 + 𝑀)𝑔

S . No.

Mass of Pan (𝒑)

No. of loops (𝑛)

Length of cord (𝐿)

1

38 gm

30 gm

2

38 gm

45 gm

66708 𝑔𝑚 − 𝑐𝑚/𝑠𝑒𝑐 2

3

124cm

49.2 Hertz or 49.2 cycles/sec

81423 𝑔𝑚 − 𝑐𝑚/𝑠𝑒𝑐 2

3

124cm

54.44 Hertz

Mass of 1cm of cord= 𝒎 = 𝟒𝟎. 𝟐𝑿𝟏𝟎−𝟒 gm

Theoretical value of Frequency = 50 Hertz

Frequency 𝝑=

𝒏 𝑻 𝟐𝑳 𝒎

Longitudinal mode

𝒏 𝒏 𝑻 𝑛 𝑇 𝐹𝑜𝑟𝑚𝑢𝑙𝑎𝑒 𝑢𝑠𝑒𝑑 𝜗= 𝝑𝝑 = = 𝟐𝑳 𝟐𝑳 𝒎 𝐿 𝑚

Procedure same as discussed above for Transverse mode

Measurement for Longitudinal mode [Procedure same as discussed above]

S . No.

Mass of Pan (𝒑)

Mass in pan (𝑀)

Total Tension 𝑇= 𝒑 + 𝑀 𝑔 𝑔 = 981 𝒄𝒎/𝒔𝒆𝒄𝟐

No. of loops (𝑛)

Mass of 1cm of cord= 𝒎

Theoretical value of Frequency = 50 Hertz

Length of cord (𝐿)

Frequency 𝝑=

𝒏 𝑻 𝑳 𝒎