Physics Times 07.2019

For T.I.R at coated surface

sin

3

c

n

 

Appling snell’s law at first surface

sin 3sin(75 ) c

sin60 3sin(75 ) c

3

3sin(75 )

2 c

 

1

sin(75 )

2 c

 

30 75 c c 45 

(^123) 1.50
3 2^2
n
  n  
4.Sol:
 m 226.005 222.000 4.000 0.005amu  
 Q value 0.005 931.5 4.655  MeV
Also
.
.
Rn
Rn
K E m
K E m




4

.. 4.44
Rn Rn 222

m

K E K E

m



   

(^) 0.08MeV
^ Energyof Photon 4.655 (4.44  
0.08)
0.135MeV KeV 135
5.Sol: For the first collision
(^) x 1 1
R
V u V
T
    
For the total journey
1 2
1
1 2
....
( )
....
m
m
R R R
V n
 T T T
  
  
  
1 1 2 2
1 2
2 2 2
.....
2 2 2
....
m m
m
x y x y x y
y y y
u u u u u u
g g g
u u u
g g g
  

 
1
2 4 2
1
2
1 1 1 ....^1
0.8
1 1 1
1 ...
m
x
m
u    v
  
    
 
 
     
 
1
2
1
1
1 1
0.8 4
1
1
1 1
V
V
 



 
 
 
  
     
  
 
 
  
 
6.Sol: Bvl10 1 10^2   ^1
 10 ^3 volt
3
1 10 (1 )^1
1
Rt
i e L e
R
    
    
 
i10 (1 0.37)^3 
i0.63mA
SECTION-3
1.Sol: Fundamental frequency is maximum when
length is minimum i.e. L 0 ,
Case1:
0
0 0 0 1
0
1
, , ;
2
T
L L T T f f f
L 
   
Case 2:
0 0
3
0
1
2 3 3
T f
f
L 
 
Case 3:
0 0
3
0
1
2 3 3
T f
f
L 
 
Case 4:
4.Sol:
5.Sol:
6.Sol:
SECTION-3
1.Sol:
Case1:
Case 2:
Case 3:
Case 4:
2.Sol: Case1:
0 0
4
0
1
2 4 2
T f
f
L 
 
2.Sol: Case1: L L T T f f 0 ,  0 ,  0
0
0
0
1
2
T
f
L 
