Question

An object is placed 15cm away from a convex mirror of focal length 45 cm.calculate the position of image and its magnification

​

Answer 1

$\Large\red{\underline{\underline{\bf{\blue{Given}}}}}$

• Object distance (u) = -15 cm ( Distance of object is always taken as negative)

• Focal length (f) = +45 cm ( Focal length of convex mirror is taken as positive)

$\Large\red{\underline{\underline{\bf{\blue{ToFind}}}}}$

• Image distance (v) = ?

$\Large\red{\underline{\underline{\bf{\blue{Solution}}}}}$

$\large\tt{\boxed{\boxed{\green{By\:using\:Mirror's\:Formula}}}}$

➠ 1/45 = 1/-15 + 1/v

➠ 1/45 + 1/15 = 1/v

➠ 1/45 + 1×3/15×3 = 1/v

➠ (1 + 3)/45 = 1/v

➠ 4/45 = 1/v

➠ v = 45/4 = 11.25 cm

Now

➦ Image distance (v) = 11.25 cm

We know that,

➦ Magnification (m) = -v/u

So, we get

➠ m = -11.25/15

➠ m = -7.5

$\tt{\red{\underline{Negative\:sign\:shows\:that\:image\:formed}}}$

$\tt{\red{\underline{is\:real\:and\:inverted}}}$

Answer 2

Object distance (u) = -15 cm ( Distance of object is always taken as negative)

Focal length (f) = +45 cm ( Focal length of convex mirror is taken as positive)

ToFind

Image distance (v) = ?

Solution

ByusingMirror

′

sFormula

➠ 1/45 = 1/-15 + 1/v

➠ 1/45 + 1/15 = 1/v

➠ 1/45 + 1×3/15×3 = 1/v

➠ (1 + 3)/45 = 1/v

➠ 4/45 = 1/v

➠ v = 45/4 = 11.25 cm

Now

➦ Image distance (v) = 11.25 cm

We know that,

➦ Magnification (m) = -v/u

So, we get

➠ m = -11.25/15

➠ m = -7.5

Negativesignshowsthatimageformed

isrealandinverted