Self Studies

Light Reflection and Refraction Test - 77

Result Self Studies

Light Reflection and Refraction Test - 77
  • 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
    The time required to pass the light through a glass slab of 2 mm2\ mm thick is (μglass=1.5)(\mu_{glass}=1.5)
    Solution
    As we know,
    t=μxc=1.5×2×1033×108=1011sect=\dfrac {\mu x}{c}=\dfrac {1.5\times 2\times 10^{-3}}{3\times 10^8}=10^{-11} sec
  • Question 2
    1 / -0
    Which of the following ray diagram show physically possible refraction
    Solution
    When light ray goes from denser to rarer medium (i.e. more μ\mu to less μ\mu) it deviates away from the normal

    On the other hand, if light ray goes from rarer to denser medium (i.e. less μ\mu to more μ\mu) it bends towards the normal. 

    It is followed only in option A.

    In option B, the refracted ray is on the same side of the normal as the incident ray, which never happens in case of any refraction. So it is incorrect.
  • Question 3
    1 / -0
    A medium shows the relation between the angle of incidence ii and the angle of refraction rr. If speed of light in the medium is ncnc then value of nn is 

    Solution
    Let μ\mu be the refractive index of the medium.
    From Snell's law: μ=sin isin r\mu=\dfrac{sin\ i}{sin\ r}
    From graph it is clear that tan30o=sinrsini\tan 30^{o}=\dfrac{\sin r}{\sin i}
    13=sinrsini=1μμ=3\Rightarrow \dfrac{1}{\sqrt{3}}=\dfrac{\sin r}{\sin i}=\dfrac{1}{\mu}\Rightarrow \mu=\sqrt{3}
    Also, speed of light in the medium v=cμ=ncn=1μ=13=(3)1/2v=\dfrac{c}{\mu}=nc\Rightarrow n=\dfrac{1}{\mu}=\dfrac{1}{\sqrt{3}}=(3)^{-1/2}
  • Question 4
    1 / -0
    A concave mirror of focal length 15 cm15\ cm forms an image having twice the linear dimensions of the object. The position of the object when the image is virtual will be 
    Solution
    Given,
    f=15 cmf=-15\ cm; focal length
    m=±2 m=\pm 2; magnification(Positive because image is virtual)
    We know that-
    m=vu\Rightarrow m=-\dfrac{v}{u}
    v=2u.\Rightarrow v=-2u.
    By using mirror formula-
    1f=1v+1u\dfrac{1}{f}=\dfrac{1}{v}+\dfrac{1}{u}

    115=1(2u)+1u\Rightarrow \dfrac{1}{-15}=\dfrac{1}{(-2u)}+\dfrac{1}{u}

    u=7.5 cm\Rightarrow u=-7.5\ cm
  • Question 5
    1 / -0
    The ratio of thickness of plates of two transparent medium AA and BB is 6:46:4. If the takes equal time in passing through them, then refractive index of BB with respect to AA will be
    Solution
    Time taken by light to travel distance xx through a medium of refractive index μ\mu is
    t=μxcμBμA=xAxB=64AμB=32=1.5t=\dfrac {\mu x}{c}\Rightarrow \dfrac {\mu_B}{\mu_A}=\dfrac {x_A}{x_B}=\dfrac {6}{4}\Rightarrow _A\mu_B =\dfrac {3}{2}=1.5
  • Question 6
    1 / -0
    An object 1 cm1\ cm tall is placed 4 cm4\ cm infront of a mirror. In order to produce an upright image of 3 cm3\ cm height one needs a
    Solution
    Erect and enlarged image can be produced by a concave mirror.
    From the definition of magnification we get,
    m=Height of the imageHeight of the object=+31=+3m=\dfrac{\text{Height of the image}}{\text{Height of the object}}=+\dfrac{3}{1}=+3
    We also know that m=vu=+3m=-\dfrac{v}{u}=+3      v=3u=3×(4)=12 cm\Rightarrow v=-3u=-3\times (-4)=12\ cm

    Using mirror formula we get 1v+1u=1f\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}
    112+14=1f\therefore \dfrac{1}{12}+\dfrac{1}{-4}=\dfrac{1}{f}
    1312=1f\Rightarrow \dfrac{1-3}{12}=\dfrac{1}{f}
    f=6 cm\Rightarrow f=-6\ cm

    The radius of curvature of the mirror is R=2f=2×6=12 cmR=2f=2\times 6 = 12\ cm, and it is a concave mirror as the focal length is -ve. 
  • Question 7
    1 / -0
    What is the time taken (in s)(in\ s) to cross a glass of thickness 4 mm4\ mm and μ=3\mu=3 by light?
    Solution
    Thickness of the glass, d=4 mm=4×103 md = 4\ mm = 4 \times 10^{-3}\ m
    Refractive index of the glass μ=3\mu = 3  
    We know
    μ=Speed of light in vacuumSpeed of light in glass=cv\mu = \dfrac{\text{Speed of light in vacuum}}{\text{Speed of light in glass}} = \dfrac{c}{v}  

    3=3×108v3 = \dfrac{3 \times 10^{8}}{v}  

    v=1×108 m/s\Rightarrow v = 1 \times 10^{8}\ m/s

    Speed=distancetime\text{Speed} = \dfrac{\text{distance}}{\text{time}}  

    time=distancespeed=4×103 m1×108 m/s\Rightarrow \text{time} = \dfrac{\text{distance}}{\text{speed}} = \dfrac{4 \times 10^{-3}\ m}{1 \times 10^{8}\ m/s}  

    time,t=4×1011 s\text{time}, t = 4 \times 10^{-11}\ s
  • Question 8
    1 / -0
    A convex mirror has a focal length f.f. A real object is placed at a distance ff in front of it from the pole produces an image at 
    Solution
    Here focal length =f=f and u=fu=-f
    On putting these values in 1f=1u+1v\dfrac{1}{f}=\dfrac{1}{u}+\dfrac{1}{v}
    1f=1f+1vv=f2\Rightarrow \dfrac{1}{f}=-\dfrac{1}{f}+\dfrac{1}{v}\Rightarrow v=\dfrac{f}{2}
  • Question 9
    1 / -0
    Match List II with List IIII and select the correct answer using the codes given below the lists:
    List IIList IIII
    (Position of the object)(Magnification)
    (I) An object is placed at focus before a convex mirror (A) Magnification is - \infty
    (II)An object is placed at centre or curvature before a concave mirror (B) Magnification is 0.50.5
    (III) An object is placed at focus before a concave mirror (C) Magnification is +1+1
    (IV) An object is placed at centre or curvature before a convex mirror  (D) Magnification is 1-1
    (E) Magnification is 0.330.33
    Solution

  • Question 10
    1 / -0
    The absolute refractive indices of water glass and diamond are 1.77, 1.50, and 2.72 respectively, which medium is most optically denser?
    Solution
    Diamond
    The optically denser medium has a larger refractive index as compared to the optically rarer medium. In this medium speed of light is minimum.
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