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1.A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in f

ID: 1454331 • Letter: 1

Question

1.A thin lens of focal length 12.5 cm has a 5.0 cm tall object placed 10 cm in front of it. Where will the image be formed?

2.5 cm behind the lens

5.6 cm behind the lens

5.6 cm in front of the lens

50 cm behind the lens

2.According to Huygens' principle, every point on a wave front acts as a source of a new _________ wave.

transverse

spherical

longitudinal

sinusoidal

plane

3. Specular reflection occurs whenever

rays reflect from a surface

rays reflect in all directions from a surface

rays reflect at only one angle from a surface.

parallel rays reflect at the same angle from a surface.

visible light rays reflect.

Explanation / Answer

1.

f = + 12.5 cm

object distance, do = 10 cm

Applying,

1/f = 1/di + 1/do

1/12.5 = 1/di + 1/10

di = - 50 cm

so image will be 50 cm in front of the lesn

that is not any options that means lens must have been diverging lens.

f = -12.5 cm


1/(-12.5) = 1/di + 1/10

di = - 5.6 cm

image will be 5.6 cn in front of lens.

2.spherical

3. parallel rays reflect at the same angle from a surface.