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                                                                    Liquid Crystal Technology 
       MCQ’s 
1 
 
 
1. Liquid crystal was first observed by 
a. Botanist 
b. Chemist 
c. Physicist 
d. Zoologist 
2. Liquid crystal was first observed by 
a. Robert Hook 
b. William Reinteizer 
c. Friendrich Reinteizer 
d. Robert Reinteizer  
3. The amount of energy needed for a 
phase transition is called 
a. Heat of fusion                               
b. Heat of transition 
c. Latent heat of transition             
d. Latent heat of fusion 
4. Which type of molecules shows the 
molecular arrangement shown in 
following  figure 
 
 
     
    a. Solid   b. liquid   
     c. Gaseous  d. Liquid crystal 
5. First liquid crystal phase discovered in a 
compound: 
a. Cholesteryl benzoate 
b. Cholesteryl proponoate 
c. Cholesteryl ethanoate 
d. Cholesteryl methaoate 
6. Transition temperature of Cholesteryl 
benzoate  is:  
a. 145°C  
b. 165°C 
 
c. 126°C 
d. 178°C 
7. Melting point of Cholesteryl benzoate  
is:  
a. 145°C  
b. 165°C 
c. 125°C 
d. 178°C 
8. Mesomorphic state refers to: 
a. Solid state 
b. Liquid state 
c. Liquid crystal state 
d. Gaseous state 
9. The point at which solid changes into 
turbid liquid (liquid crystals) is known as 
a.     Melting point                              
b. Transition point                                                
c.    boiling point                                  
d. Eutectic point 
10. The point at which turbid liquid changes 
into clear liquid is called  
a.     Melting point                               
b. Transition point                                                
c.    Eutectoid point                                 
d. Eutectic point 
11. How many triple points are shown by 
following curve ? 
Page 2


                                                                    Liquid Crystal Technology 
       MCQ’s 
1 
 
 
1. Liquid crystal was first observed by 
a. Botanist 
b. Chemist 
c. Physicist 
d. Zoologist 
2. Liquid crystal was first observed by 
a. Robert Hook 
b. William Reinteizer 
c. Friendrich Reinteizer 
d. Robert Reinteizer  
3. The amount of energy needed for a 
phase transition is called 
a. Heat of fusion                               
b. Heat of transition 
c. Latent heat of transition             
d. Latent heat of fusion 
4. Which type of molecules shows the 
molecular arrangement shown in 
following  figure 
 
 
     
    a. Solid   b. liquid   
     c. Gaseous  d. Liquid crystal 
5. First liquid crystal phase discovered in a 
compound: 
a. Cholesteryl benzoate 
b. Cholesteryl proponoate 
c. Cholesteryl ethanoate 
d. Cholesteryl methaoate 
6. Transition temperature of Cholesteryl 
benzoate  is:  
a. 145°C  
b. 165°C 
 
c. 126°C 
d. 178°C 
7. Melting point of Cholesteryl benzoate  
is:  
a. 145°C  
b. 165°C 
c. 125°C 
d. 178°C 
8. Mesomorphic state refers to: 
a. Solid state 
b. Liquid state 
c. Liquid crystal state 
d. Gaseous state 
9. The point at which solid changes into 
turbid liquid (liquid crystals) is known as 
a.     Melting point                              
b. Transition point                                                
c.    boiling point                                  
d. Eutectic point 
10. The point at which turbid liquid changes 
into clear liquid is called  
a.     Melting point                               
b. Transition point                                                
c.    Eutectoid point                                 
d. Eutectic point 
11. How many triple points are shown by 
following curve ? 
                                                                    Liquid Crystal Technology 
       MCQ’s 
2 
 
 
a. Two 
b. Three 
c. Four 
d. One 
12. Liquid crystal molecules have structure 
like: 
a. Cylinder 
b. Spherical 
c. Rod 
d. Circular 
13.  Liquid crystal which flow like near 
normal flow behavior of liquids 
a. Smectic liquid crystals                      
b. Nematic liquid crystals 
c. Chlorestic liquid crystals                  
d. None of above 
14. The appearance of nematic phase of 
liquid crystal is  
a. Gel Like Substance  
b. Thread like substance 
c.  Slippery substance  
d. Much thicker substance 
15. Liquid crystal molecules possess: 
a. Transational order 
b. Vibrational order 
c. Intrinsic order 
d. Orientational order 
16. The distinguishing characteristic of the 
liquid crystalline state is the tendency of 
the molecules (mesogens) to point 
along a common axis, is called 
a.     Director                                              
b. Orientational order                                              
c.      Positional order                                
d. Theta  
17. The amount of order  is measured by: 
a. 3 cos
2
?-1/2 
b.  3 cos
2
?-2/2 
c. 3 cos
2
?-1/3 
d. 3 cos
2
?-2/3 
17. Order parameter depends upon 
a. Temperature 
b. Pressure 
c. Viscosity 
d. Surface Tension 
18. In order parameter vs Temperature 
graph, 
   
Tc refers to: 
a. Critical temperature 
b. Transition temperature 
c. Melting point 
d. Boiling point 
Page 3


                                                                    Liquid Crystal Technology 
       MCQ’s 
1 
 
 
1. Liquid crystal was first observed by 
a. Botanist 
b. Chemist 
c. Physicist 
d. Zoologist 
2. Liquid crystal was first observed by 
a. Robert Hook 
b. William Reinteizer 
c. Friendrich Reinteizer 
d. Robert Reinteizer  
3. The amount of energy needed for a 
phase transition is called 
a. Heat of fusion                               
b. Heat of transition 
c. Latent heat of transition             
d. Latent heat of fusion 
4. Which type of molecules shows the 
molecular arrangement shown in 
following  figure 
 
 
     
    a. Solid   b. liquid   
     c. Gaseous  d. Liquid crystal 
5. First liquid crystal phase discovered in a 
compound: 
a. Cholesteryl benzoate 
b. Cholesteryl proponoate 
c. Cholesteryl ethanoate 
d. Cholesteryl methaoate 
6. Transition temperature of Cholesteryl 
benzoate  is:  
a. 145°C  
b. 165°C 
 
c. 126°C 
d. 178°C 
7. Melting point of Cholesteryl benzoate  
is:  
a. 145°C  
b. 165°C 
c. 125°C 
d. 178°C 
8. Mesomorphic state refers to: 
a. Solid state 
b. Liquid state 
c. Liquid crystal state 
d. Gaseous state 
9. The point at which solid changes into 
turbid liquid (liquid crystals) is known as 
a.     Melting point                              
b. Transition point                                                
c.    boiling point                                  
d. Eutectic point 
10. The point at which turbid liquid changes 
into clear liquid is called  
a.     Melting point                               
b. Transition point                                                
c.    Eutectoid point                                 
d. Eutectic point 
11. How many triple points are shown by 
following curve ? 
                                                                    Liquid Crystal Technology 
       MCQ’s 
2 
 
 
a. Two 
b. Three 
c. Four 
d. One 
12. Liquid crystal molecules have structure 
like: 
a. Cylinder 
b. Spherical 
c. Rod 
d. Circular 
13.  Liquid crystal which flow like near 
normal flow behavior of liquids 
a. Smectic liquid crystals                      
b. Nematic liquid crystals 
c. Chlorestic liquid crystals                  
d. None of above 
14. The appearance of nematic phase of 
liquid crystal is  
a. Gel Like Substance  
b. Thread like substance 
c.  Slippery substance  
d. Much thicker substance 
15. Liquid crystal molecules possess: 
a. Transational order 
b. Vibrational order 
c. Intrinsic order 
d. Orientational order 
16. The distinguishing characteristic of the 
liquid crystalline state is the tendency of 
the molecules (mesogens) to point 
along a common axis, is called 
a.     Director                                              
b. Orientational order                                              
c.      Positional order                                
d. Theta  
17. The amount of order  is measured by: 
a. 3 cos
2
?-1/2 
b.  3 cos
2
?-2/2 
c. 3 cos
2
?-1/3 
d. 3 cos
2
?-2/3 
17. Order parameter depends upon 
a. Temperature 
b. Pressure 
c. Viscosity 
d. Surface Tension 
18. In order parameter vs Temperature 
graph, 
   
Tc refers to: 
a. Critical temperature 
b. Transition temperature 
c. Melting point 
d. Boiling point 
                                                                    Liquid Crystal Technology 
       MCQ’s 
3 
 
19. Order parameter of liquid crystal is in 
range of 
a. 0-5 
b. 0-10 
c. 2-8 
d. 1-10 
20.  Order parameter for liquid is 
                    a. 0                       
                    b. 1                                  
                    c.    0-1                                  
                    d. Infinity 
21. Order parameter of solid is equal to 
 a. 0                                    
 b. 1                                  
 c.    0-1                                  
 d. Infinity 
22.  Order parameter __________ with 
increase in temperature 
a.     increases                                   
b. decreases                                 
c.    does not change                        
d. Abruptly increases 
23. Lyotropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
24. Thermrtropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
25. Liquid crystal molecules possess 
a.  Sinlgle indices of 
refraction 
b. Multiple indices of 
refraction 
c. Two different indices of 
refraction 
d. None of above 
26. Which of the following is not a property 
of liquid crystals 
a.     Long range order                                 
b. Flexible ends                             
c.    Rigid central region                              
d. No functional groups 
27.  Liquid crystal state is also called as 
a. Triple phase                                      
b. Nematic phase     
c. Mesomorphic state  
d. Polymer dispersed phase 
28. Which liquid phase has no positional 
order but the director n is at a constant 
tilt angle measured normal to the 
surface of the layer 
    a.     Smectic A                             
     b. Smectic B                                                
                 c.    Smectic C                             
                d. Nematic 
 
29. Under polarized light, nematic phase 
appears like 
a. Thread like 
b. Fan-like 
c. Rope-like 
d. Wheel-like  
30. Which of the following property of 
liquid crystal resembles that of liquids 
a.     Fluidity                                
b. Anisotropy in magnetic properties                                                    
c.    Anisotropy in optical properties                        
d. Double refraction 
Page 4


                                                                    Liquid Crystal Technology 
       MCQ’s 
1 
 
 
1. Liquid crystal was first observed by 
a. Botanist 
b. Chemist 
c. Physicist 
d. Zoologist 
2. Liquid crystal was first observed by 
a. Robert Hook 
b. William Reinteizer 
c. Friendrich Reinteizer 
d. Robert Reinteizer  
3. The amount of energy needed for a 
phase transition is called 
a. Heat of fusion                               
b. Heat of transition 
c. Latent heat of transition             
d. Latent heat of fusion 
4. Which type of molecules shows the 
molecular arrangement shown in 
following  figure 
 
 
     
    a. Solid   b. liquid   
     c. Gaseous  d. Liquid crystal 
5. First liquid crystal phase discovered in a 
compound: 
a. Cholesteryl benzoate 
b. Cholesteryl proponoate 
c. Cholesteryl ethanoate 
d. Cholesteryl methaoate 
6. Transition temperature of Cholesteryl 
benzoate  is:  
a. 145°C  
b. 165°C 
 
c. 126°C 
d. 178°C 
7. Melting point of Cholesteryl benzoate  
is:  
a. 145°C  
b. 165°C 
c. 125°C 
d. 178°C 
8. Mesomorphic state refers to: 
a. Solid state 
b. Liquid state 
c. Liquid crystal state 
d. Gaseous state 
9. The point at which solid changes into 
turbid liquid (liquid crystals) is known as 
a.     Melting point                              
b. Transition point                                                
c.    boiling point                                  
d. Eutectic point 
10. The point at which turbid liquid changes 
into clear liquid is called  
a.     Melting point                               
b. Transition point                                                
c.    Eutectoid point                                 
d. Eutectic point 
11. How many triple points are shown by 
following curve ? 
                                                                    Liquid Crystal Technology 
       MCQ’s 
2 
 
 
a. Two 
b. Three 
c. Four 
d. One 
12. Liquid crystal molecules have structure 
like: 
a. Cylinder 
b. Spherical 
c. Rod 
d. Circular 
13.  Liquid crystal which flow like near 
normal flow behavior of liquids 
a. Smectic liquid crystals                      
b. Nematic liquid crystals 
c. Chlorestic liquid crystals                  
d. None of above 
14. The appearance of nematic phase of 
liquid crystal is  
a. Gel Like Substance  
b. Thread like substance 
c.  Slippery substance  
d. Much thicker substance 
15. Liquid crystal molecules possess: 
a. Transational order 
b. Vibrational order 
c. Intrinsic order 
d. Orientational order 
16. The distinguishing characteristic of the 
liquid crystalline state is the tendency of 
the molecules (mesogens) to point 
along a common axis, is called 
a.     Director                                              
b. Orientational order                                              
c.      Positional order                                
d. Theta  
17. The amount of order  is measured by: 
a. 3 cos
2
?-1/2 
b.  3 cos
2
?-2/2 
c. 3 cos
2
?-1/3 
d. 3 cos
2
?-2/3 
17. Order parameter depends upon 
a. Temperature 
b. Pressure 
c. Viscosity 
d. Surface Tension 
18. In order parameter vs Temperature 
graph, 
   
Tc refers to: 
a. Critical temperature 
b. Transition temperature 
c. Melting point 
d. Boiling point 
                                                                    Liquid Crystal Technology 
       MCQ’s 
3 
 
19. Order parameter of liquid crystal is in 
range of 
a. 0-5 
b. 0-10 
c. 2-8 
d. 1-10 
20.  Order parameter for liquid is 
                    a. 0                       
                    b. 1                                  
                    c.    0-1                                  
                    d. Infinity 
21. Order parameter of solid is equal to 
 a. 0                                    
 b. 1                                  
 c.    0-1                                  
 d. Infinity 
22.  Order parameter __________ with 
increase in temperature 
a.     increases                                   
b. decreases                                 
c.    does not change                        
d. Abruptly increases 
23. Lyotropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
24. Thermrtropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
25. Liquid crystal molecules possess 
a.  Sinlgle indices of 
refraction 
b. Multiple indices of 
refraction 
c. Two different indices of 
refraction 
d. None of above 
26. Which of the following is not a property 
of liquid crystals 
a.     Long range order                                 
b. Flexible ends                             
c.    Rigid central region                              
d. No functional groups 
27.  Liquid crystal state is also called as 
a. Triple phase                                      
b. Nematic phase     
c. Mesomorphic state  
d. Polymer dispersed phase 
28. Which liquid phase has no positional 
order but the director n is at a constant 
tilt angle measured normal to the 
surface of the layer 
    a.     Smectic A                             
     b. Smectic B                                                
                 c.    Smectic C                             
                d. Nematic 
 
29. Under polarized light, nematic phase 
appears like 
a. Thread like 
b. Fan-like 
c. Rope-like 
d. Wheel-like  
30. Which of the following property of 
liquid crystal resembles that of liquids 
a.     Fluidity                                
b. Anisotropy in magnetic properties                                                    
c.    Anisotropy in optical properties                        
d. Double refraction 
                                                                    Liquid Crystal Technology 
       MCQ’s 
4 
 
31. Liquids possess 
a. anisotropy                              
b.  orientational order 
c. Isotropy                                  
d. positional order 
32. Under polarized light, cholesteric liquid 
crystal have appearance like  
a. Finger print                              
b. Thread  
c. helix 
d. fan 
33. Which of the following property of 
liquid crystal resembles that of solids 
  a.  Fluidity                                
b.  Formation of droplets                            
c.   Anisotropy                             
d.   Isotropy 
34.  Which liquid crystal phase has fan like 
structure under polarized light ? 
 a.     Smectic                                 
 b.    Nematic                               
 c.    Cholesteric                             
 d.   Polymer dispersed  
35. Which liquid crystal phase has gel like 
appearance? 
a.  Smectic                                 
b. Nematic                               
c.  Cholesteric                             
d. Polymer dispersed 
36. Newtonian flow behavior is adopted by 
a. Nematic 
b. Smectic-A 
c. Smectic-B 
d. Smectic-C 
37. The flow of true liquid is: 
a. Newtonian 
b. Non- Newtonian 
c. Far- Newtonian 
d. Near- Newtonian 
38. Flow of Smectic liquid crystal is 
a. Newtonian 
b. Non- Newtonian 
c. Far- Newtonian 
d. Near- Newtonian 
39. Nematic  phase possess 
a. Positional order 
b. Translational order 
c. Orientational order 
d. Vibrational order 
40. Pitch is measured in case of ________ 
liquid crystals 
a.     Smectic                               
b. Nematic                               
c.    Cholesteric                            
d. Polymer dispersed 
 
41. In the following diagram, ‘n’ represents 
 
a. Long axis of molecules 
b. Molecular axis 
c. Director 
d. Direction of molecules 
42. Which type of molecules are depicted in 
following figure 
Page 5


                                                                    Liquid Crystal Technology 
       MCQ’s 
1 
 
 
1. Liquid crystal was first observed by 
a. Botanist 
b. Chemist 
c. Physicist 
d. Zoologist 
2. Liquid crystal was first observed by 
a. Robert Hook 
b. William Reinteizer 
c. Friendrich Reinteizer 
d. Robert Reinteizer  
3. The amount of energy needed for a 
phase transition is called 
a. Heat of fusion                               
b. Heat of transition 
c. Latent heat of transition             
d. Latent heat of fusion 
4. Which type of molecules shows the 
molecular arrangement shown in 
following  figure 
 
 
     
    a. Solid   b. liquid   
     c. Gaseous  d. Liquid crystal 
5. First liquid crystal phase discovered in a 
compound: 
a. Cholesteryl benzoate 
b. Cholesteryl proponoate 
c. Cholesteryl ethanoate 
d. Cholesteryl methaoate 
6. Transition temperature of Cholesteryl 
benzoate  is:  
a. 145°C  
b. 165°C 
 
c. 126°C 
d. 178°C 
7. Melting point of Cholesteryl benzoate  
is:  
a. 145°C  
b. 165°C 
c. 125°C 
d. 178°C 
8. Mesomorphic state refers to: 
a. Solid state 
b. Liquid state 
c. Liquid crystal state 
d. Gaseous state 
9. The point at which solid changes into 
turbid liquid (liquid crystals) is known as 
a.     Melting point                              
b. Transition point                                                
c.    boiling point                                  
d. Eutectic point 
10. The point at which turbid liquid changes 
into clear liquid is called  
a.     Melting point                               
b. Transition point                                                
c.    Eutectoid point                                 
d. Eutectic point 
11. How many triple points are shown by 
following curve ? 
                                                                    Liquid Crystal Technology 
       MCQ’s 
2 
 
 
a. Two 
b. Three 
c. Four 
d. One 
12. Liquid crystal molecules have structure 
like: 
a. Cylinder 
b. Spherical 
c. Rod 
d. Circular 
13.  Liquid crystal which flow like near 
normal flow behavior of liquids 
a. Smectic liquid crystals                      
b. Nematic liquid crystals 
c. Chlorestic liquid crystals                  
d. None of above 
14. The appearance of nematic phase of 
liquid crystal is  
a. Gel Like Substance  
b. Thread like substance 
c.  Slippery substance  
d. Much thicker substance 
15. Liquid crystal molecules possess: 
a. Transational order 
b. Vibrational order 
c. Intrinsic order 
d. Orientational order 
16. The distinguishing characteristic of the 
liquid crystalline state is the tendency of 
the molecules (mesogens) to point 
along a common axis, is called 
a.     Director                                              
b. Orientational order                                              
c.      Positional order                                
d. Theta  
17. The amount of order  is measured by: 
a. 3 cos
2
?-1/2 
b.  3 cos
2
?-2/2 
c. 3 cos
2
?-1/3 
d. 3 cos
2
?-2/3 
17. Order parameter depends upon 
a. Temperature 
b. Pressure 
c. Viscosity 
d. Surface Tension 
18. In order parameter vs Temperature 
graph, 
   
Tc refers to: 
a. Critical temperature 
b. Transition temperature 
c. Melting point 
d. Boiling point 
                                                                    Liquid Crystal Technology 
       MCQ’s 
3 
 
19. Order parameter of liquid crystal is in 
range of 
a. 0-5 
b. 0-10 
c. 2-8 
d. 1-10 
20.  Order parameter for liquid is 
                    a. 0                       
                    b. 1                                  
                    c.    0-1                                  
                    d. Infinity 
21. Order parameter of solid is equal to 
 a. 0                                    
 b. 1                                  
 c.    0-1                                  
 d. Infinity 
22.  Order parameter __________ with 
increase in temperature 
a.     increases                                   
b. decreases                                 
c.    does not change                        
d. Abruptly increases 
23. Lyotropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
24. Thermrtropic mesomorphism  in a 
substance is introduced by 
a. Adding solute 
b. Increasing pressure 
c. Increasing temperature 
d. Adding Solvent 
25. Liquid crystal molecules possess 
a.  Sinlgle indices of 
refraction 
b. Multiple indices of 
refraction 
c. Two different indices of 
refraction 
d. None of above 
26. Which of the following is not a property 
of liquid crystals 
a.     Long range order                                 
b. Flexible ends                             
c.    Rigid central region                              
d. No functional groups 
27.  Liquid crystal state is also called as 
a. Triple phase                                      
b. Nematic phase     
c. Mesomorphic state  
d. Polymer dispersed phase 
28. Which liquid phase has no positional 
order but the director n is at a constant 
tilt angle measured normal to the 
surface of the layer 
    a.     Smectic A                             
     b. Smectic B                                                
                 c.    Smectic C                             
                d. Nematic 
 
29. Under polarized light, nematic phase 
appears like 
a. Thread like 
b. Fan-like 
c. Rope-like 
d. Wheel-like  
30. Which of the following property of 
liquid crystal resembles that of liquids 
a.     Fluidity                                
b. Anisotropy in magnetic properties                                                    
c.    Anisotropy in optical properties                        
d. Double refraction 
                                                                    Liquid Crystal Technology 
       MCQ’s 
4 
 
31. Liquids possess 
a. anisotropy                              
b.  orientational order 
c. Isotropy                                  
d. positional order 
32. Under polarized light, cholesteric liquid 
crystal have appearance like  
a. Finger print                              
b. Thread  
c. helix 
d. fan 
33. Which of the following property of 
liquid crystal resembles that of solids 
  a.  Fluidity                                
b.  Formation of droplets                            
c.   Anisotropy                             
d.   Isotropy 
34.  Which liquid crystal phase has fan like 
structure under polarized light ? 
 a.     Smectic                                 
 b.    Nematic                               
 c.    Cholesteric                             
 d.   Polymer dispersed  
35. Which liquid crystal phase has gel like 
appearance? 
a.  Smectic                                 
b. Nematic                               
c.  Cholesteric                             
d. Polymer dispersed 
36. Newtonian flow behavior is adopted by 
a. Nematic 
b. Smectic-A 
c. Smectic-B 
d. Smectic-C 
37. The flow of true liquid is: 
a. Newtonian 
b. Non- Newtonian 
c. Far- Newtonian 
d. Near- Newtonian 
38. Flow of Smectic liquid crystal is 
a. Newtonian 
b. Non- Newtonian 
c. Far- Newtonian 
d. Near- Newtonian 
39. Nematic  phase possess 
a. Positional order 
b. Translational order 
c. Orientational order 
d. Vibrational order 
40. Pitch is measured in case of ________ 
liquid crystals 
a.     Smectic                               
b. Nematic                               
c.    Cholesteric                            
d. Polymer dispersed 
 
41. In the following diagram, ‘n’ represents 
 
a. Long axis of molecules 
b. Molecular axis 
c. Director 
d. Direction of molecules 
42. Which type of molecules are depicted in 
following figure 
                                                                    Liquid Crystal Technology 
       MCQ’s 
5 
 
 
 
 
a. Nematic 
b. Smectic A 
c. Smectic B 
d. Smectic C 
43. In laptops, LCD's display material used is  
a.  TN display material  
b.  STN display material 
c. FLC display material  
d.  ECB display material 
44. The following arrangement is shown by 
 
a. Smectic  A 
b. Smectic B 
c. Nematic 
d. Chlolestric 
45. In diagram of Q. 44, what ‘a’ depicts? 
a. Director 
b. Pitch 
c. Half Pitch 
d. Length 
46. Which application of Liquid crystal 
technology is influenced by ‘a’ ? 
a. Liquid crystal display 
b. Optical imaging 
c. Liquid crystal thermometer 
d. Thermography 
47. In diagram of Q.44, which pattern is 
followed by its director in structure? 
a. Spherical 
b. Helical 
c. Circular 
d. Semi-circular  
48. The molecules align in layers, this 
causes the director n orientation to 
rotate slightly between the layers, 
eventually bringing the molecules back 
into the original orientation. The 
distance required to achieve this is 
known as 
                   a. Director                            
                   b. Half pitch                                               
                   c.    Pitch                              
                   d. Order  
49.  Thickness of  layer of Chlolesteric phase 
is 
a. 50-500 molecules 
b. 500-5000 molecules 
c. 50-5000 molecules 
d. 500-500000 molecules 
50. Which property changes the magnitude 
of pitch in cholesteric phase? 
a. Temperature 
b. Pressure 
c. Viscosity 
d. Surface tension 
51. Layered structure is shown by 
a. Nematic 
b. Smectic 
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FAQs on Liquid crystal mcqs - Class 12

1. What are liquid crystals?
Ans. Liquid crystals are a state of matter that exhibit properties of both liquids and solids. They have a fluid-like behavior but also possess an ordered molecular arrangement.
2. How are liquid crystals used in displays?
Ans. Liquid crystals are commonly used in displays, such as LCD screens, because of their ability to change their optical properties when subjected to an electric field. By applying an electric current to the liquid crystal molecules, their alignment changes, allowing light to pass through or be blocked, resulting in the formation of images or text on the display.
3. What are the different types of liquid crystals?
Ans. There are mainly three types of liquid crystals: nematic, smectic, and cholesteric. Nematic liquid crystals have a long-range order of orientation but no positional order. Smectic liquid crystals have both long-range orientation and positional order. Cholesteric liquid crystals have a periodic helical structure.
4. How do liquid crystals react to temperature changes?
Ans. Liquid crystals are sensitive to temperature changes. When heated, the molecules in the liquid crystal become more disordered, causing a change in their optical properties. This temperature-dependent behavior is utilized in thermochromic liquid crystals, which change color with temperature variations.
5. Are liquid crystals harmful to health?
Ans. Liquid crystals used in everyday applications, such as displays, are generally considered safe and not harmful to health. However, certain chemicals used in the production of liquid crystals may have health risks associated with them. It is important to handle and dispose of liquid crystal devices properly, following the manufacturer's guidelines and local regulations.
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