e/m by Thomson's Experiment - Write up : practical

e/m by Thomson's Experiment - Write up
1. AIM : e/m by Thompson's Experiment

2. APPARATUS : Thompson's Experiment Set-up, magnetometer, Two bar magnets.

3. FORMULA :  

4. DIAGRAM : 

4. PROCEDURE : i) Adjust the position of magnetometer. Magnet m Magnetometer should be stable in north-south direction. Adjust the pointer in East-West direction so that the earth's magnetic Field should not affect the deflection in Magnetometer i.e. the deflecting angle. Fix the positions of magnets equidistant from CRT. Keeping the wooden bench in east west direction. Measure the deflecting angles by two sides of pointer. (θ1 and θ2) 
ii) Plot the graph between X (cm) and Bx (Wb/m^2). From Observation Table No. 1
iii) Make the calculations as per Observation Table No. 2.
iv) Calculate the value of e/m from given and observed data it should be equal to 1.75 X 10^{11 C/Kg}

5. OBSERVATIONS : i)  Deflection (D) = ---
                                      ii) Voltage applied on YY' plates.(V) =-- 
                                      iii) Position of Magnets =-----
                                      iv) Distace of centre of YY' plates to 
                                            screen(k+l/2)=---
                                        v) length of YY' plates (l) =----

6. OBSERVATION TABLE :

Sr No.	X(cm)	Ө1	Ө2	Ө (avg of Ө1 and Ө2)	Tan Ө	Bx = B0 tan Ө

Observation Table (1)

Sr No.	X(cm)	Bx ( by graph)	Bx .dx	ʃ Bx .dx	ʃ Bx .dx.dx	ʃ ʃ Bx .dx.dx

 Observation Table (2)

7. GRAPH (if any) :

8. CALCULATIONS (from Graph) : Calculate the value of e/m from given values and observed data.

9. RESULT (with SI unit) : The experimental value of e/m is calculated as..................
10. PRECAUTIONS : i) The position of magnets should be fixed.
ii) Adjust the glow at origin without any deflection.   
iii) Do not disturb the position of wooden bench and magnets.