Tag: option c: imaging

Quizzes (13) Questions (113)

Questions Related to option c: imaging

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

A prism of a certain angle deviates the red and blue rays by $8$ and $12$ respectively. Another prism of the same angle deviates the red and blue rays by $10$ and $14$ respectively. The prisms are small angled and made of different materials. The dispersive powers of the materials of the prisms are in the ratio

  1. $11 : 9$
  2. $6 : 5$
  3. $9 : 11$
  4. $5 : 6$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Dispersive power $= \cfrac{\mu _v - \mu _r}{\mu _y -1} = \cfrac{\delta _v + \delta _r}{\delta _y}$

$\delta _y = \cfrac{\delta _v + \delta _r}{2}$

The ratio of dispersive power is;
$\cfrac{12-8}{\cfrac{12+8}{2}}$= $\cfrac{\cfrac{4}{10}}{\cfrac{4}{12}}$ =$ \cfrac{12}{10} $= $ 6 : 5 $

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

When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is.

  1. Polarised

  2. Of longer wavelength largest

  3. Of shorter wavelength

  4. Of high intensity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The resolving power of an instrument depends upon the wave length of light used. The lower the wavelength of light higher is the accuracy in vision.
$\left(Resolving\, power \,\alpha \frac{1}{\lambda}\right)$

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

Calculate the dispersive power for glass from the given data $\mu _v=1.523$, and $\mu _r=1.5145$.

  1. 0.0012

  2. 0.2333

  3. 0.1639

  4. 0.9
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mean refractive index   $\mu = \dfrac{\mu _v+\mu _r}{2} = \dfrac{1.523+1.5145}{2} = 1.5192$

Dispersive power   $w = \dfrac{\mu _v - \mu _r}{\mu -1}$
$\implies \ w = \dfrac{1.523 - 1.5145}{1.5192 -1} = 0.01637$

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

If the refractive indices of a prism for red, yellow and violet colours be 1.61, 1.63 and 1.65 respectively, then the dispersive power of the prism will be:

  1. $\dfrac { 1.65-1.62 }{ 1.61-1 }$
  2. $\dfrac { 1.62-1.61 }{ 1.65-1 }$
  3. $\dfrac { 1.65-1.61 }{ 1.63-1 }$
  4. $\dfrac { 1.65-1.63 }{ 1.61-1 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dispersive power of the prism=$\dfrac{\mu _v-\mu _r}{\mu _y-1}=\dfrac{1.65-1.61}{1.63-1}$

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

A reflecting telescope has a large mirror for its objective with radius of curvature equal to 80 cm. The magnifying power of this telescope if eye piece used has a focal length of 1.6 cm is:

  1. 100

  2. 50

  3. 25

  4. 5
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The focal length of objective mirror $f _0 = \dfrac{R}{2} = \dfrac{80}{2} = 40 \,cm$
and focal length of eye piece = 1.6 cm
$\therefore $ magnifying power, $m = \dfrac{f _0}{f _e} = \dfrac{40}{1.6 } = 25$

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

A telescope is used to resolve two stars separated by $4.6 \, \times \, 10^{-6}$ rad. If the wavelength of light used is 5460 $\overset{0}{A}$, what should be the aperture of the objective of the telescope? 

  1. 0.1488 m

  2. 0.567 m

  3. 1 m

  4. 2 m
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aperature of the telescope, $D = \dfrac{1.22\lambda}{d\theta}$ 


Here, $\lambda = 5460\ \overset{0}{A} = 5460 \times 10^{-10}m$


$ d\theta= 4.6 \times10^{-6}\ rad$

$\therefore D = \dfrac{1.22\times5460\times10^{-10}}{4.6\times 10^{-6}}$
$ = 0.1488m $

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 option c: imaging optical instruments : telescope the reflecting telescope optical telescope xx radio telescope and space telescopes
Which material should be chosen to make the concave mirrors of a high resolution telescope so that it can also withstand temperature variations?

  1. Quartz

  2. Flint glass

  3. Crown glass

  4. Combination of Flint and Silica
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Quartz makes an ideal mirror. Its high hardness results in the smoothest micropolished surface possible, and its thermal dimensional stability allows the optician to produce a flat surface with almost no edge defects.

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

Scientists identify the elements that are burning in the stars by using which of the following devices?

  1. Refractive telescopes

  2. Reflective telescopes

  3. Spectroscopes

  4. Polarimeters

  5. Photoelectric mircoscopes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Using the spectroscope, scientists can separate the individual line spectra of the elements that are burning in the stars and therefore identify the elements.