Self Studies
Self Studies
Self Studies
Self Studies

Ray Optics Test - 5

Result Self Studies

Ray Optics Test - 5
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0
    At Kavalur in India, astronomers using a telescope whose objective had a diameter of 1 m started using a telescope of diameter 2.54 m. This resulted in
    Solution
    Resolving power of telescope ; where D is diameter of the objective.
    So, on using the telescope of diameter 2.54 m in place of 1 m, the resolving power will increase by 2.54 times for the same .
  • Question 2
    1 / -0
    A lens of focal length 50 cm forms an image of a distant object, which subtends an angle of 1 milliradian at the lens. What is the size of the image?
    Solution
    If length of Image Is I, then angle subtended by the object at the lens = angle subtended by the image at the lens.
    i.e. =





  • Question 3
    1 / -0
    A telescope has an objective of focal length 200 cm and an eyepiece of focal length 5 cm. What is the magnification of the telescope?
    Solution
    Magnification of telescope =
    Or magnification of telescope = or 40
  • Question 4
    1 / -0
    The principal section of a glass prism is an isosceles triangle ABC with AB = AC. One face AC of the glass prism is silvered as shown in the figure. If a ray is incident normally on the face AB and after two reflections, it emerges from the base BC perpendicular to it, what is the measure of angle BAC?

    Solution


    From the figure,
    β = 2α
    In the given triangle, 2α + 2α + α = 180°
    5α = 180°
    α = 36°
  • Question 5
    1 / -0
    Each quarter of a vessel of depth 'H' is filled with liquids of refractive indices n1, n2, n3 and n4 from the bottom. The apparent depth of the vessel, when observed normally, is
    Solution
    We know, (where n2 is refractive index of the medium and n1 is refractive index of the outside)
    Bottom depth from the top of inside layer I =
    Bottom depth from the top of inside layer II = +

    Bottom depth from the top of inside layer III =

    Bottom depth from the top of inside layer IV =

    Depth from outside =
  • Question 6
    1 / -0
    Material A has a critical angle iA and material B has a critical angle iB (iB > iA).

    Which of the following statements are true?

    (i) Light can be totally internally reflected when it passes from B to A.
    (ii) Light can be totally internally reflected when it passes from A to B.
    (iii) The critical angle for total internal reflection is iB - iA.
    (iv) The critical angle between A and B is .
    Solution
    If and are the refractive indices of A and B, respectively, then

    and

    ,



    iB > iA (given)

    >

    >

    Light suffers total internal reflection on moving from denser to rarer medium. Light from A to B can suffer total internal reflection. Hence, (i) is false and (ii) is true.

    Critical angle at interface of B and A = sin -1= sin -1 = sin -1

    Hence, (iv) is true.

    Also, iB - iA = sin -1- sin -1

    sin-1

    sin-1

    Critical angle = sin-1

    Hence, (iii) is incorrect.
  • Question 7
    1 / -0
    A pIano-convex lens acts like a concave mirror of 28 cm focal length when its plane surface is silvered and like a concave mirror of 10 cm focal length when its curved surface is silvered. What is the refractive index of the material of the lens?
    Solution
  • Question 8
    1 / -0
    If a ray of light in a denser medium enters into a rarer medium at an angle of incidence i, the angles of reflection and refraction are r and r', respectively. If the reflected and refracted rays are at right angle to each other, then the critical angle for the given pair of media is
    Solution

  • Question 9
    1 / -0
    In the visible region, the dispersive powers and the mean angular deviations for crown and flint glass prisms are and , and d and d', respectively. When the two prisms are combined, the condition of zero dispersion of the combination is
    Solution
  • Question 10
    1 / -0
    A ray of light passes from vacuum into a medium of refractive index , and the angle of incidence is found to be twice the angle of refraction. Then, angle of incidence is
    Solution
  • Question 11
    1 / -0
    A ray of light passes through an equilateral prism such that an angle of incidence is equal to the angle of emergence, and the latter is equal to th the angle of prism. The angle of deviation is
    Solution
    Angle of incidence = angle of emergence,
    ie, i = i'
    Also, i' = × angle of equilateral prism
    = × 60° = 45°

    Thus, angle of deviation δ
    = i + i' - A
    δ = (45° + 45° - 60°) = 30°
  • Question 12
    1 / -0
    Directions: For the given statements of assertion and reason, mark the correct answer as follows:

    (a) If both assertion and reason are true and reason is the correct explanation of assertion.
    (b) If both assertion and reason are true, but reason is not the correct explanation of assertion.
    (c) If assertion is true, but reason is false.
    (d) If both assertion and reason are false.

    Assertion:     A biconvex lens of focal length 10 cm is split into two equal parts by a plane parallel to its principal axis. The focal length of each part will be 20 cm.
    Reason:     Focal length does not depend on radii of curvature of two surfaces.
    Solution
    When lens is split parallel to principle axis ,it will not change focal length of lens,it will change in amount of light entering in each part.So assertion is wrong.Focal length depends on radius of curvature,thus reason is also false.

  • Question 13
    1 / -0
    The refractive index of glass with respect to a medium is 4/3. If the difference between the velocities of light in medium and in glass is 6.25 x 107 m/s, then what is the velocity of light in the medium?
    Solution
  • Question 14
    1 / -0
    A bird in air looks at a fish vertically below it inside water. X is height of the bird above the surface of water, and Y is depth of the fish below the surface of water. If the refractive index of water with respect to air is , the distance of the fish as observed by the bird is
    Solution
    True Depth/Apparent Depth = μ
    Apparent Depth = Y/μ
    As bird is at a height X, the distance of the fish as observed by the bird is X + Y/μ.
  • Question 15
    1 / -0
    A given ray of light suffers minimum deviation in an equilateral prism P. Additional prisms Q and R of identical shape and material are now added to P (as shown in the figure). The ray will suffer

    Solution
    Since net deviation caused by prisms Q and R is zero, so the ray will suffer the same deviation.
  • Question 16
    1 / -0
    A thin prism P1 with angle 4° made from a glass of refractive index 1.54 is combined with another thin prism P2 made from glass of refractive index 1.72 to produce dispersion without deviation. The angle of the prism P2 is
    Solution
  • Question 17
    1 / -0
    One of the refracting surfaces of a prism of refractive indexis silvered. The angle of the prism is equal to critical angle of a medium of refractive index 2. A ray of light incident on the unsilvered surface passes through the prism and retraces its path after reflection at the silvered face. Then, the angle of incidence on the unsilvered surface is
    Solution
  • Question 18
    1 / -0
    A small telescope has an objective lens of focal length 144 cm and an eyepiece of focal length 6.0 cm. What is the magnifying power of the telescope and the separation between the objective lens and the eyepiece?
    Solution
    Focal length of the objective lens, fo = 144 cm
    Focal length of the eyepiece, fe = 6.0 cm
    The magnifying power of the telescope is given as



    The separation between the objective lens and the eyepiece is calculated as:



    L = 144 + 6 = 150 cm

    Hence, the magnifying power of the telescope is 24, and the separation between the objective lens and the eyepiece is 150 cm.
  • Question 19
    1 / -0
    A microscope is focused on a mark on a piece of paper. A slab of glass of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark in focus again?
    Solution
    Apparent depth of the mark = = 2 cm
    This means the mark has apparently moved up by 1 cm. The apparent distance of the mark is 2 cm. So, the microscope has to be moved upward by 1 cm.
  • Question 20
    1 / -0
    A ray of light is incident normally on one face of a right-angled isosceles prism. Then, it grazes the hypotenuse. The refractive index of material of the prism is
    Solution
  • Question 21
    1 / -0
    A light ray is travelling between two media as given below. The angle of incidence on the boundary in all the cases is 30o. Identify the correct sequence of increasing order of angles of refraction.

    (1) Air to water
    (2) Water to glass
    (3) Glass to water
    (Refractive indices of glass and water are and , respectively.)
    Solution
  • Question 22
    1 / -0
    What is the time taken by sunlight to pass through a window of thickness 4 mm, whose refractive index is ?
    Solution
    As the optical path travelled by the light is d = x (x is the thickness of the window), time taken by the sunlight to travel through the window is:

  • Question 23
    1 / -0
    White light is incident on one of the refracting surfaces of a prism of angle 5°. If refracting indices for red and blue colours are 1.659 and 1.641, respectively, then the angular dispersion between these two colours, when they emerge out of the prism, is
    Solution
  • Question 24
    1 / -0
    A prism of refractive index has a refracting angle of 60o. At what angle must a ray be incident on it so that it suffers a minimum deviation?
    Solution

  • Question 25
    1 / -0
    If light travels distance 'x' in 't1' seconds in air and distance '10x' in 't2' seconds in another medium, then what will be the critical angle of that medium?
    Solution
Self Studies
User
Question Analysis

  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now