For an object at distance of 3.00 m, at what distance from the lens is the image formed? the person is farsighted ?

You want this nearsighted person to be able to see very distant objects clearly. That means the spectacle lens must produce an image 30.0 cm from the eye for an object very far away. An image 30.0 cm from the eye will be 28.5 cm to the left of the spectacle lens (see Figure 2). Therefore, we must get di = −28.5 cm when do ≈ ∞. The image distance is negative, because it is on the same side of the spectacle as the object

Explanation:

Since do are known, the power of the spectacle lens can be found using

P

=

1

d

o

+

1

d

i

as written earlier:

P

=

1

d

o

+

1

d

i

=

1

∞

+

1

−

0.285

m

Since

1

∞

=

0

, we obtain:

P

=

0

−

3.51

m

=

−

3.51

D

okay i have so many questions. but the big one here is: um wt..f is this mess? ?

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27