Physics Times – July 2019

(Darren Dugan) #1
2

(^24)
2 cos 2 0.075 cos 60
3.75cm
1000 2 10 10
o
T
h
rg




 
  
  
Case-
Therefore, Option (a) is correct
Case-
(2) Liquid will rise only upto height of 5 cm
and meniscus will adjust by changing its
radius of curvature.
If the liquid goes up in tube 2 then it will
not be able to support the weight of the
liquid
(3) Weight of water in meniscus will be
different in two cases because angle of
contact is different.
(4) Case-1I
7.Sol: For 1 2
1 2( 1)n
n n n
f R

   (1)
1
1 1 1
(n 1)
f R
    
 
 
2
1 1 1
(n n 1)
f R
      
 
 
1 ( 1) 1
( 1)
n
n n
f f R R
  
      
   
1 2 n n 2
f f R
  

  (2)
(1)/ (2) 
2( 1)
2 2
n
f f R
f n n
R

 

  
2( 1)
1
2 2
f n
f n n
 
 
  
(^) (2 2)
f n
f n n
 

  
3
2
3 0
10
2 10
20 3 10 2
f
f




      
 
 f 0 0.02cm
8.Sol:
1 2 1 2 0
3 4 3 4 0
2
/
P
P
Q nC T T
Q nC T T
 
 
 
  
 
Case-
Case-
Case-1I
7.Sol:
8.Sol:
1 2 1 2
2 3 2 3
5
3
P P
V V
Q nC T C
Q nC T C
 
 
 
  
 
0 0
cycle 0 0 2 2
T RT
W  PV nR  
 
option (c) is wrong as no adiabatic process is
involved
Correct options are a,b

Free download pdf