Physics

Optics and Lenses

251 Questions

Enhance your physics knowledge by practicing questions on optics and the functioning of lenses. The set covers calculating combined focal lengths, lens power, and correcting vision defects like myopia and hypermetropia. These physics fundamentals are crucial for medical entrance and state board exams.

Combined focal lengthCorrecting vision defectsLens power calculationConvex and concave lensesTelescopesHuygens principle

Optics and Lenses Questions

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 .

Multiple choice conditions for a light ray to pass undeviated refraction of light at plane surfaces physics

A small object is enclosed in a sphere of solid glass  $8 cm$  in radius. It is situated  $2 cm$  from centre and is viewed from the side to which it is nearest. Where will it appear to be it  $\mu$  of glass  $= 1.5$ ?

  1. $6 cm$
  2. $4 cm$
  3. $5\dfrac { 1 }{ 3 } { cm }\quad $
  4. $3\dfrac { 2 }{ 3 } { cm }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Using refraction at a spherical surface, light travels from the object inside the glass sphere to the nearer surface. The object distance u = -2 cm, radius of curvature R = -8 cm, and refractive indices are mu_1 = 1.5 and mu_2 = 1. Applying the formula (mu_2/v) - (mu_1/u) = (mu_2 - mu_1)/R, we get (1/v) - (1.5/-2) = (1 - 1.5)/(-8), which simplifies to (1/v) + 0.75 = 0.0625, leading to v = -16/3 cm = -5 1/3 cm, meaning it appears 5 1/3 cm from the surface.

Multiple choice perceive colours resolution of optical instruments lenses option c: imaging physics

The focal length of a thin convex lens for red and blue rays are $100\ cm$ and $96.8\ cm$ respectively. The dispersive power of the material of the lens is

  1. 0.0325

  2. 0.825

  3. 0.968

  4. 0.98
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dispersive power (omega) for a thin lens is (f_r - f_b) / f_mean. f_mean = (100 + 96.8) / 2 = 98.4. Omega = (100 - 96.8) / 98.4 = 3.2 / 98.4 = 0.0325.

Multiple choice physics option c: imaging optical instruments : telescope the reflecting telescope optical telescope xx radio telescope and space telescopes

If you want to make Refracting Telescope, what components will you choose ?

  1. One convex led and one concave lens.

  2. Two convex lenses.

  3. One concave mirror, one plane mirror and one convex lens.

  4. Once concave mirror, one convex mirror and one convex lens.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A refracting telescope uses two convex lenses: an objective lens to gather light and an eyepiece lens to magnify the image.

Multiple choice physics observing space: telescopes optical instruments : telescope the reflecting telescope optical telescope xx radio telescope and space telescopes

Match the items given in A, B, C and D against their corresponding description given in 1, 2, 3, 4 and 5.
A. Astronomical telescope
B. Galilean Telescope
C. Simple Microscope
D. Compound Microscope

1. Contains one convex lens
2. Contains one concave lens
3. Contains a convex lens of large focal length in the objective and a convex lens of small focal length in the eye-piece
4. Contains a convex lens of small focal length in the objective and a convex lens of large focal length in the eye-piece
5. Contains a convex lens of large focal length in the objective and a concave lens of small focal length in the eye-piece. 

  1. $2\, \quad\, 3\, \quad\, 1\, \quad\, 5$
  2. $3\, \quad\, 2\, \quad\, 4\, \quad\, 1$
  3. $2\, \quad\, 5\, \quad\, 3\, \quad\, 4$
  4. $3\, \quad\, 5\, \quad\, 1\, \quad\, 4$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A). Astronomical telescope - Contains a convex lens of large focal length in the objective and a convex lens of small focal length in the eye-piece

B.) Galilean Telescope - Contains a convex lens of large focal length in the objective and a concave lens of small focal length in the eye-piece
C). Simple Microscope - Contains one convex lens
D.) Compound Microscope - Contains a convex lens of small focal length in the objective and a convex lens of large focal length in the eye-piece
Thus,
A  -  3 , B  -  5 , C  -  1 and D  -  4 , hence Option D is correct.

Multiple choice newton's colour disc light and the formation of shadows physics

When a drop of water is introduced between the glass plate and plano-convex lens in Newton's rings system, the ring system

  1. Contracts

  2. Expands

  3. Remains same

  4. First expands then contracts
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The diameter of Newton's rings is inversely proportional to refractive index. Therefore when a drop of water is introduced between the glass plate and plano-convex lens in Newton's rings, the ring system contacts. 

Multiple choice newton's colour disc light and the formation of shadows physics

In the Newton's rings set up, when a drop of water is introduced between the glass plate and planoconvex lens the observed ring system

  1. Contracts

  2. Expands

  3. Remains the same

  4. Expands and then contracts
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since diameter of the ring is inversely proportional to the square root of refractive index of the medium between the planoconvex lens and plane glass plate, therefore as refractive index increases, diameter of the rings decrease, that is the rings contract. 

Multiple choice evs light and shadow dual nature of light nature and sources of light theories on light

Which of the following is incorrect?

  1. A thin convex lens of focal length ${f} _{1}$ is placed in contact with a thin concave lens of focal length ${f} _{2}$. The combination will act as convex lens if ${f} _{1}<{f} _{2}$
  2. Light on reflection at water-glass boundary will undergo a phase change of $\pi$

  3. Spherical aberration is minimized by achromatic lens

  4. If the image of distant object is formed in front of the retina then defect of vision may be myopia
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice evs light and shadow dual nature of light nature and sources of light theories on light

The inability of a lens to bring all the rays coming from a point object to focus at one single point is called

  1. Spherical aberration

  2. Parallex

  3. Optical illusion

  4. none
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Spherical aberration occurs when a lens cannot focus all rays from a point source to a single point due to the spherical shape of the lens surfaces.