Question

a needle of height 1.5 cm is placed at distance of 20 cm from a concave mirror of a focal length 15 cm at what distance from the mirror should a spring be placed in order to receive a sharph image what is the nature and size of the image of the needle is move closer to the mirror how would the screen have to be moved​

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Physics

Ray Optics and Optical Instruments

Spherical Mirrors

A 1\ cm height needle is ...

PHYSICS

A 1 cm height needle is placed at a distance of 0.1 m from a convex mirror of focal length 0.05 m, then size of the image is

October 15, 2019

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Ramna Mall

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ANSWER

Object distance u=−0.1 m

Focal length f=0.05 m

Using mirror formula

v

1

+

u

1

=

f

1

∴

v

1

+

−0.1

1

=

0.05

1

⟹ v=

30

1

cm

Object height h

o

=1 cm

Magnification m=

h

o

h

i

=

u

−v

∴

1

h

i

=

30×(−0.1)

−1

⟹ h

i

=0.33 cm