Question

the focal length of a convex mirror is 10cm and the object distance is 20cm. Determine (a) the image distance (b) the magnification of image....☺✌​

Answer 1

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

$\Large{\underline{\mathfrak{\orange{\bf{Given}}}}}$

• The Focal Length (f) = - 10 cm
• The Object Distance (d') = 20 cm

Where,

Negative sign (Focal length ) indicate that the focal point of concave mirror is virtual .

$\Large{\underline{\mathfrak{\orange{\bf{Using\:Formula}}}}}$

★ 1/f = 1/d' + 1/d"

Where,

• d" = distance of image .

$\Large{\underline{\underline{\mathfrak{\red{\bf{Explanation}}}}}}$

Now, keep Value of f & d' .

➠ 1/(-10) = 1/20 + 1/d"

➠ 1/d" = - 1/10 - 1/20

➠ 1/d" = (-2 - 1)/20

➠ 1/d" = -3/20

➠ d" = -20/3

➠ d" = -6.7 cm

$\Large{\underline{\mathfrak{\orange{\bf{Hence}}}}}$

• The Length of image will be (d") = -6.7 cm

$\Large{\underline{\mathfrak{\blue{\bf{Note}}}}}$

• Here, negative sign indicate that image is virtual.

The Magnification of image :-

$\Large{\underline{\mathfrak{\orange{\bf{Using\:Formula}}}}}$

★ Magnification (m) = - d"/d'

Keep Value of d' & d"

➠ m = -(- 6.7)/20

➠m = 6.7/20

➠ m = 67/200

➠ m = 0.3 [ Ans ].

$\Large{\underline{\mathfrak{\blue{\bf{Note}}}}}$

• Positive sign indicate that the image is upward .
• Diagram attached .

________________

Answer 2

Answer:

We know, convex mirror always forms the virtual, upright and diminished. Also, Object distance in the convex mirror is always negative where as Image distance and focal length are positive. v=? magnification of the image= -3/20.