Answer:
0.22mm
Explanation:
A far sighted person is a person suffering from long sightedness i.e such individual can only see far distant object clearly but not near distant object. The defect is corrected using convex lens.
Since convex lens is used, the focal (f) length of the lens is positive and the image distance (v) is also positive.
Using the lens formula,
1/f = 1/u + 1/v
Where u is the object distance = 0.35mm
v = 0.6mm
1/f = 1/0.35+1/0.6
1/f = 2.86 + 1.67
1/f = 4.53
f = 1/4.53
f = 0.22mm
The focal length of the contact lenses will be 0.22mm
Answer: 8000N
Explanation: since it is frictionless that means it has 100% efficiency therefore the mechanical advantage is 1 meaning the load equals to the effort
\Delta L= \alpha L_0 (T_f-T_i)
= (18 x 10^-6 /°C)(0.125 m)(100° C - 200 °C)
= -0.00225 m
New length = L + ΔL
= 1.25 m + (-0.00225 m)
= 1.248
So your answer is B.
