# Distance between the object and the lens

## Homework Statement

A diverging lens of 6 mm focal length produces an image of magnification m = 1/2. What
is the distance between the object and the lens?

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tiny-tim
Homework Helper
Welcome to PF!

## Homework Statement

A diverging lens of 6 mm focal length produces an image of magnification m = 1/2. What
is the distance between the object and the lens?
Hi Libra_girl ! Welcome to PF!

Hint: what equations do you know that relate the size of the object to the size of the image?

Hi Libra_girl ! Welcome to PF!

Hint: what equations do you know that relate the size of the object to the size of the image?

Is it the equation: do/di = m or 1/do + 1/di = 1/f ?

tiny-tim
Homework Helper
Is it the equation: do/di = m or 1/do + 1/di = 1/f ?
Both equations!

Except isn't it m = -di/do?

Both equations!

Except isn't it m = -di/do?

yeah it is sorry

Last edited:
yeah it is sorry
Both equations!

Except isn't it m = -di/do?
Ok so I know f and I know m, now I am solving for do, but I don't know the di?

alphysicist
Homework Helper
Hi Libra girl,

You now have two equations in two unknowns. You can solve the magnification formula for one of the variables and plug it into the other formula. What does that give?