Ch 9. Ray Optics And Optical Instruments Flashcards by Zahid !

The radius of curvature of each surface of a biconvex lens is 20cm and the refractive index of the material of the lens is 1.5.
The focal length of the lens is

20 cm

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A convex lens of focal length 40 cm and a concave lens of focal length 29 cm are in contact. The power of their combination in diootre is

-2.5

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Light year is equal to

9.46 × 10¹⁵

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A spherical mirror is immersed in water. It’s focal length will

Remain same

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The coefficient of reflection for total internal reflection will be

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The critical angle for total internal reflection of a ray from any medium to vaccum is 30•Degree. Then velocity of light in the medium will be

μ = 1/sinC, Va/Vm = 1/sinC, Vm = 3× 10⁸ × 1/2 = 1.5 × 10⁸ m/s

V niche a, V niche m, V niche m

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In visible spectrum, which colour has larger wavelength

Red

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The dispersive power of a prism depends on

Nature of material of prism

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The final image formed by a terrestrial telescope is

Virtual and erect compared to the object

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The unit of which physical quantity is light year?

Distance

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Which of the following is correct for refractive index of mean colour (yellow colour) ?

µ = µr + µv/2

Neeche r and v

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Power of parallel sided glass-slab is

Zero

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Angular dispersion is equal to

(µv - µr) A

Neeche v and r

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Which of the following relations is correct for dispersive power?

ω = µv - µr/µy - 1

Neeche v, r and y

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Velocity of light in vacuum is c. its value in glass
(µ = 3/2) will be

2c/3

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The power of convex lens of focal length 20 cm in dioptre is

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The velocity of light is maximum in

Vaccum

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The refractive index of diamond is about

2.42

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Optical path is equal to

Refractive index × path-length

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A convex lens (µ = 1.5) is immersed in water
(µ = 1.33), then it will behave as

Converging lens

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Light owes its colour to its

Frequency

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The solar spectrum is

Continuous

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Which one of the following has maximum refractive index?

Diamond has maximum refractive index

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Equivalent focal length of two lenses in contact having power
-15D and +5D will be

-10cm

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A convex lens is dipped in a liquid, whose refractive index is equal to refractive index of material of lens. Then it's focal length will

Become infinite

Critical angle for light moving from medium I to medium II is θ. The speed of light in medium I is v. Then speed in medium II is

V/Sin θ

Magnifying glass is to be used at the fixed object distance of 1 inch. if it is to produce an erect mage 5 times magnified, its focal length should be

1.25"

Which of the following phenomena takes place when monochromatic light is incident on a prism?

Dispersion

The critical angle of light passing from glass to air is minimum for

Violet colour

The angle of minimum deviation for thin prism of refractive index (µ) is

(µ -1) A

The focal length of a lens µ = 1.5 in air is 20cm. Its focal length in medium of refractive index 1.5 is

♾️

The optical fibre works on the principle of

Total internal reflection

Transverse nature of light is shown by

Polarization

When to converging lenses of same focal length f are placed in contact, then the focal length of the combination is

f/2

How many images are formed by the lens if an object is kept on its axis? µ₁ µ₃ µ₂ µ₄

Statement 1st : For focal length of a convex lens 1/f = (µ-1) (1/r₁ - 1/r₂) Statement 2nd : for local length of red colour of light is maximum

Both the statements are true, but Statement 2 is not the correct explanation of statement 1

For the following question number 28 to 30 A paragraph is a given. You have to first go through that given paragraph and then answer the following three questions by indicating correct option. Paragraph When a ray passes through a prism, refraction takes place as shown in figure : Q. Angle of emergence is

Angle α is

(180° - A)

When a ray passes symmetrically through a prism it suffers minimum deviation. Here

A/2

When a ray of light enters a glass slab, its wavelength

Decreases

Image formed by a concave spherical mirror is

Virtual, Real, Magnified, Inverted Ans - All of the above

A biconvex lens (µ = 1.5) has equal curvature each of 20 cm. The power of the lens is

5 D

Monochromatic light of wavelength 6000 A in vacuum enters a medium of refractive index 1.5. The wavelength of it in this medium is

4000A°

When light travels from one medium to another which of the following factors change?

Wavelength and frequency Both A and B

If angle of incidence is i' > i, then angle of refraction is

< i'

If angle of incidence is i' > 2 i, then angle of refraction is

< 2i

For what value of angle of incidence total internal reflection (TIR) takes place?

For No value

The image formed at the retina of human eye is

Inverted

A path length t in a glass of refractive index n is equivalent to ----- path length in vacuum.

The radius of curvature of plane mirror is

Infinite

SI unit of power of lens is

Dioptre

Statement 1: Light travels in a straight line in a homogeneous medium Statement 2 : in diffraction light changes its path without any change in the medium

Statement 1 is true, but Statement 2 is false.

₁µ₂ is equal to

µ₂/µ¹

Which of the following is the cause of formation of rainbow?

Refraction

The focal length of a lens of capacity 4 dioptre is

0.25 m

If the focal length of a glass lens (µ = 3/2) in air is f a and in water (µ = 4/3) is f w then a and w neeche

fw = 4fa w and a neeche

Which of the following relations is correct for intensity of scattered light ( I ) and wavelength of light (λ)?

I ∝ 1/λ⁴

Power of two lenses in contact is

P = P₁ + P₂

If µ g = 3/2 and µ w = 4/3 then w µ g is Neeche g and w and w and g again

9/8

Critical angle for glass is

42° (nearly)

Critical angle for transparent medium diamond is

24.41°

The refractive index of material of the prism is

µ = sin (A+δm/2)/sin A / 2 Neeche m

Which of the following is correct for astronomical telescope?

fo > fe Neeche o and e

The image formed by simple microscope is

Virtual and erect

Which of the following eye defects is removed by convex lens?

Far sightedness

Focal length of eye lens of a healthy man is about

25cm

The length of an astronomical telescope for normal adjustment is

fo + fe Neeche o and e

On increasing the length of the tube of compound microscope, magnifying power

Increases

The lens which is used to remove short sightedness is

Concave

Which of the relations is correct for the magnifying power of compound microscope?

M = - L/f₀ ( 1 + D/fe) Neeche e

The magnifying power of an astronomical telescope for normal adjustment is

- f₀/fe Neeche e

Cylindrical lenses are used to correct the eye defect called

Astigmatism

The image formed by objective lens of a compound microscope is

Real and Large

Which lens is used to remove hypermetropia?

Convex

The resolving power of human eye (in minute) is

1/60

What lens does a short sighted person uses for clear vision?

Concave lens

When the tube length of microscope is increased, its magnifying power

Increases

The final image in astronomical telescope is

Virtual and inverted

The magnifying power of magnifying glass of power 12 dioptre is

Image formed on retina is

Real and inverted

Magnifying power of simple microscope is

M = 1 + D/f