Question

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Answer 1

h=1 cm
u=-15 cm
f=-10 cm

1/f=1/v+1/u
1/v=1/f-1/u
1/v=-1/10+1/15
1/v=-15+10/150
1/v=-5/150
1/v=-1/30cm
v=-30 cm



2.Light travels faster in water than kerosene because of it's lower density.
Water have lower density than kerosene .

Answer 2

Object height (h) = 1cm

Object distance (u) = -15 cm [Object distance and focal length are taken negative in Concave mirror;New Cartesian Sign Convension]

Focal length (f) = -10 cm

We know, 1/v + 1/u = 1/f [Mirror formula]

Therefore, 1/v = 1/f - 1/u

1/v = 1/(-10) - 1/(-15)

1/v = 1/(-10) + 1/15 [(-) x (-) = (+)]

1/v = 5/(-150) [Cross-multiplying]

v = -150/5 = -30 cm


2)It is because water has less refractive index and we know that refractive index is inversely proportional to the speed of light in that medium , Refractive index in a medium = speed of light in air/speed of light in that medium.Hope this helps!!!!!