1. What is the SI unit of surface tension?
A.
N m
B.
N/m
C.
J m
D.
Pa/m
Correct Answer:
N/m
Explanation:
The SI unit of surface tension is newton per metre (N/m), representing force per unit length.
2. Which unit is commonly used for surface tension in the CGS system?
A.
dyne/cm
B.
erg/cm²
C.
N/m
D.
Pa·s
Correct Answer:
dyne/cm
Explanation:
In the CGS system, surface tension is commonly expressed as dyne per centimetre (dyne/cm).
3. Which of the following is equivalent to 1 N/m in terms of energy per unit area?
A.
1 J/m²
B.
1 J/m
C.
1 N·m²
D.
1 Pa·m²
Correct Answer:
1 J/m²
Explanation:
Surface tension has the equivalent unit J/m² because 1 J/m² is equal to 1 N/m.
4. The dimensional formula of surface tension is:
A.
[M L T⁻²]
B.
[M L⁻¹ T⁻²]
C.
[M T⁻²]
D.
[M L² T⁻²]
Correct Answer:
[M T⁻²]
Explanation:
Surface tension is force per unit length. Since force has dimensions [M L T⁻²], dividing by length gives [M T⁻²].
5. What is the relation between dyne/cm and N/m?
A.
1 N/m = 1 dyne/cm
B.
1 N/m = 10 dyne/cm
C.
1 N/m = 100 dyne/cm
D.
1 N/m = 1000 dyne/cm
Correct Answer:
1 N/m = 1000 dyne/cm
Explanation:
Using 1 N = 10⁵ dyne and 1 m = 100 cm, 1 N/m equals 10³ dyne/cm.
6. Which unit represents surface tension as force divided by length?
A.
N/m
B.
N/m²
C.
J/m
D.
kg/m³
Correct Answer:
N/m
Explanation:
Surface tension is defined as force per unit length, so its unit is N/m.
7. A surface tension of 0.072 N/m is equal to:
A.
0.72 dyne/cm
B.
7.2 dyne/cm
C.
72 dyne/cm
D.
720 dyne/cm
Correct Answer:
72 dyne/cm
Explanation:
Since 1 N/m equals 1000 dyne/cm, 0.072 N/m equals 72 dyne/cm.
8. Which SI unit is also dimensionally equivalent to N/m for surface tension?
A.
J/m²
B.
J/m³
C.
N·m
D.
Pa·m²
Correct Answer:
J/m²
Explanation:
Because one joule equals one newton metre, J/m² simplifies to N/m, the SI unit of surface tension.
9. What is the surface tension unit in the CGS system when expressed as energy per unit area?
A.
erg/cm²
B.
erg/cm
C.
dyne·cm
D.
cal/cm
Correct Answer:
erg/cm²
Explanation:
In the CGS system, surface tension can be expressed as energy per unit area, which is erg/cm².
10. A surface tension of 50 dyne/cm is equal to:
A.
0.005 N/m
B.
0.05 N/m
C.
0.5 N/m
D.
5 N/m
Correct Answer:
0.05 N/m
Explanation:
Since 1 dyne/cm equals 0.001 N/m, 50 dyne/cm equals 0.05 N/m.
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