Tag: reflection of light and shadow

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Questions Related to reflection of light and shadow

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Fill in the blank:

When angle of incidence increases, glancing angle of incidence ________.

  1. decreases

  2. increases

  3. remains same

  4. becomes zero
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Angle of incidence $+$ Glancing angle of incidence $=90^0$

So, Glancing angle of incidence $=90^0 -$ Angle of incidence
This means, when angle of incidence increases, glancing angle of incidence decreases,

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Fill in the blank:

When the angle of incidence increases, glancing angle of reflection _______.

  1. increases

  2. remains same

  3. decreases

  4. becomes infinite
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Angle of incidence $+$ glancing angle of incidence $=90^0$

So, glancing angle of incidence $=90^0 -$ angle of incidence
Now, glancing angle of incidence $=$ glancing angle of reflection
Therefore, glancing angle of reflection $=90^0 -$ angle of incidence
This means, when angle of incidence increases, glancing angle of reflection decreases,

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Bouncing of light into the same medium, from which the light ray is incident, is termed as

  1. Refraction

  2. Diffraction

  3. Reflection

  4. Scattering
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$ \bf{Refraction} $ of light is the phenomenon of bending of light or change in the direction of light, when it passes obliquely from one transparent medium to another.

$ \bf{Diffraction} $ is the phenomenon of bending of light waves around the corners of an obstacle or aperture, placed in the path of light beam.

$ \bf{Reflection} $ is the phenomenon in which light rays on striking a polished surface(such as a mirror) bounce back or are sent back into the same medium. 

$\bf{Scattering} $ is the phenomenon by which a beam of light is redirected or deflected in many different directions when it passes through an imperfect medium due to the interaction with the particles of the medium.

Hence, the correct answer is OPTION C. 

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Reflection can occur on

  1. Transparent surfaces

  2. Translucent surfaces

  3. Opaque surfaces

  4. B and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Objects which allow the light to pass through them completely without any obstruction are called $ \bf{transparent} $ objects.
Objects which allow the light to pass through them partially are called $ \bf{translucent} $ objects.
Objects which do not allow the light to pass through them are called $\bf{opaque} $ objects.

Since, transparent objects allow light to pass through them completely, no reflection can occur on them. 

Reflection occurs on translucent surfaces because they reflect a certain amount of light while allowing a certain amount of light to be transmitted. Reflection occurs perfectly on Opaque surfaces because they reflect all the light that falls on them without allowing any light to pass through them.

Hence, the correct answer is OPTION D.
Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Which of the following is the main reason of Opacity of light waves.

  1. reflection

  2. absorption

  3. refraction

  4. diffusion

  5. transmission
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Objects are visible to the eye when light strikes the surface and reflects back itself into the eye. Opaque objects show this phenomenon.

However in the transparent objects, the incident light on their surface gets transmitted, hence does not reflect back to eye and appear transparent.

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

A ray of light striking a plane mirror at an angle of 35 degrees with the normal.

Find out the angle of reflection with normal.

  1. 35 degrees.

  2. 55 degrees.

  3. 10 degrees

  4. 90 degrees

  5. 125 degrees
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Angle of incidence    $i = 35$ degrees

According to Snell's law of reflection, the angle of incidence is equal to the angle of reflection.
$\implies$ Angle of reflection      $r = i = 35$  degrees

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

When a light ray falls on a perfectly reflective mirror at an angle. Identify which of the following statement is true about the ray?

  1. The frequency of the light ray changes

  2. The wavelength of the light ray changes

  3. The velocity of the light ray changes

  4. The period of the light ray changes

  5. The direction of motion of the light ray changes
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

When a light ray falls on a perfectly reflective mirror at some angle, then only the direction of the light rays changes such that the angle of incidence is equal to the angle of reflection but the frequency, wavelength, time period and the velocity of the light remain constant.

Thus option E is correct.

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

Identify on which of the following, specular reflection would most likely to occur. 

  1. mirror

  2. wall

  3. sheet of paper

  4. ceiling.

  5. cat's fur
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The back of a mirror is usually covered with some sort of darkly colored, protective material to stop the silver coating from getting scratched, and also to reduce the risk of any light seeping through from behind. Silver reflects light better than almost anything else and that's because it gives off almost as many light as fall on it in the first place.

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

In which of the following conditions diffuse reflection takes place?

  1. When a parallel beam of light is reflected by a plane mirror.

  2. When a parallel beam of light is reflected by a highly polished metal surface.

  3. When a parallel beam of light is reflected by a paper sheet.

  4. All of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diffuse reflection occurs when light hits a rough or irregular surface, causing it to scatter in many directions. A paper sheet has a microscopically rough surface compared to mirrors or polished metal, which produce specular reflection.

Multiple choice physics reflection of light and shadow terms related with reflection terms related to reflection of light laws of reflection

A person has a $18$cm wide face and his two eyes are separated by 8 cm.Find the minimum width of a mirror required for the person to view is face laterally is

  1. $9$cm
  2. $4$cm
  3. $5$cm
  4. $13$cm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For minimum width -

i). Center of face and mirror must lie in perpendicular bisector of the line joining two eyes.
ii). Left eye must see right end point of face at the end of the mirror.
iii). Night eye must see left end point of face at then end of the mirror.
Now let, 
$F _1,F _2$ end points of face width $11E _1,E _2$ two eyes $11C-$ center of face.
$m _1.m _2-$ mirror end points
$m _1,m _2-$ projection of $m _1m _2$ on line joining two eyes.
Now, line joining two eyes should look like -
$F _1--E _1---m _1-C---m _2----E _2---F _2$
Due to symmetry,
$\Rightarrow F1E2=E1F2=13cm$
Also, $m _1,m _2$ must be midpoint of $F1E2$ and $E1F2$ respectively.
So, $E1m2=m1E2=\dfrac{13}{2}=6.5$
$E1m2=6.5$
$\Rightarrow E1C+Cm2=6.5$
     $4+Cm2=6,5$
     $Cm2=2.5$
similarly $m1C=2.5$
$\Rightarrow m1m2=m1C1C2=5cm=$ mirror width.
Hence, the answer is $5cm.$