Tag: technical terms related to lens

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Questions Related to technical terms related to lens

Multiple choice physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

A plane-convex lens has a refractive index of 1.6 and a radius of curvature 60 cm. What is the focal length of the lens? 

  1. 50 cm

  2. 100 cm

  3. 200 cm

  4. 150 cm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

${R _1} = 60\,cm,\,\,{R _2} = \infty ,\,\,\mu  = 1.6$

$\frac{1}{f} = \left( {\mu  - 1} \right)\left( {\frac{1}{{{R _1}}} - \frac{1}{{{R _2}}}} \right)$
$\frac{1}{f} = \left( {1.6 - 1} \right)\left( {\frac{1}{{60}}} \right)$
$ = f = 100\,cm.$
Hence,
option $(B)$ is correct answer.

Multiple choice physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

Which statement is correct for a zone plate and a lens?

  1. Zone plate has multi focii whereas lens has one

  2. Zone plate has one focus whereas lens has multiple focii

  3. Both are correct

  4. Zone plane has one focus whereas a lens has infinite
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A zone plate acts like a lens with multiple foci because it is based on diffraction zones, whereas a standard refractive lens has a single focal point determined by its geometry and refractive index.

Multiple choice physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

A point on the principal axis of a lens, to which light rays parallel to the principal axis converge after passing through the lens, is ............

  1. Centre of curvature

  2. Origin

  3. Focus

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

A point on the principal axis of a lens, to which light rays parallel to the principal axis converge after passing through the lens, is  called focus of the lens.


Answer-(C).

Multiple choice physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

For which of the following is $f > 0$:

I. Concave mirror
II. Convex mirror
III. Converging lens
 

  1. I only

  2. II only

  3. I and III only

  4. II and III only

  5. I, II, and III
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In this style of multiple-choice question, the I, II, and III questions provide you with three possible answers, and the five answer choices list different combinations of those three. Theres an upside and a downside to questions like these. Suppose you know that a concave mirror has f >0 and a convex mirror doesnt, but youre not sure about a converging lens. The downside is that you cant get the right answer for sure. The upside is that you can eliminate B, D, and E, and have a 50% chance of guessing the right answer. As long as youre not afraid to guessand you should never be afraid to guess if youve eliminated an answerthese questions shouldnt be daunting. 
The value of f for a converging lens is positive, so the answer is C . 

Multiple choice physics lens technical terms related to lens terms related to lenses introduction to lenses and its types

A convex and a concave lens separated by distance $d$ are then put in contact. The focal length of the combination

  1. Decreases

  2. Increases

  3. Becomes $0$

  4. Remains the same
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\dfrac{1}{f _r}=\dfrac{1}{f _1}+\dfrac{1}{f _2}-\dfrac{d}{f _1f _2}$

So when are brought in contact $d=0$, hence focal length $f _r$ will decrease .