Question

What magnification will be produced by a lens of power –4.00 D (such as might be used to correct myopia) if an object is held 43 cm away? Your answer should be a number with two decimal places. Hint: you need to first determine the focal distance of the lens.

Answer 1

The magnification is
`m = 0.3674`

Step-by-step explanation:

From the question we are told that

The power of the lens is
`P = -4.00 D(dioptre)`

Generally
`1 dioptre = 1 \ meter`

The object distance is
`u = -43 \ cm` the negative sign is because the distance is measured in the opposite direction of incident light (i.e away )

Generally the focal length is mathematically represented as

`f = (1)/(P)`

=>
`f = (1)/(4.00 )`

=>
`f = 0.25 \ m`

converting to cm

=>
`f = 0.25 \ m = 0.25 * 100 = 25 \ cm`

Generally from lens equation we have that

`(1)/(f) +(1)/(v) -(1)/(u)`

=>
`(1)/(25) +(1)/(v) -(1)/(-43)`

=>
`v = -15.8 \ cm`

Generally the magnification is mathematically represented as

`m = (v)/(u)`

=>
`m = (- 15.8)/(-43)`

=>
`m = 0.3674`