Tag: space exploration and forms of light

Questions Related to space exploration and forms of light

Which of the following is cannot be considered as the use of space stations?

  1. Space station is used to study the effects of long-duration spaceflight on the human body

  2. Space station provides a platform for greater number and length of scientific studies than it is available on other space vehicles.

  3. Space stations are used both for military and civilian purposes.

  4. None of these


Correct Option: D
Explanation:

Space stations are made to conduct experiments that needs to be done out in space. It is used to study the effects of long-duration space flight on human body. These provides a platform for greater number and length of scientific studies than it is available on other space vehicles and other military and civilian purposes.

The number of wavelengths in the visible spectrum is :

  1. $4000$

  2. $6000$

  3. $2000$

  4. $inifinite$


Correct Option: D
Explanation:
  • The visible light spectrum is the section of the electromagnetic radiation spectrum that is visible to the human eye. 
  • It ranges in wavelength from approximately 400 nanometers ($4 \times  10 ^{-7}$ m, which is violet) to 700 nm ($7 \times 10^{-7}$ m, which is red).
  • Hence wavelengths are infinite
  • Option D is the right answer

Choose the correct answer from the alternatives given.
Which of the following ray are not electromagnetic waves

  1. X-rays

  2. $\gamma- $ rays

  3. $\beta -$ rays

  4. Heat rays


Correct Option: C
Explanation:

Cosmic rays, γ-rays, and X-rays are part of electromagnetic spectrum, while β-rays are emitted by radioactive elements. Hence β-rays is not electromagnetic waves.

The image of a distant object as seen through an astronomical telescope is

  1. Erect

  2. Inverted

  3. Disorted

  4. None


Correct Option: B
Explanation:

Astronomical telescopes uses convex lenses which form real and inverted image of object at infinite distance.

The large aperture of telescope are used for

  1. Greater magnification

  2. Greater resolution

  3. Reducing lens aberration

  4. Case ofmanufacture


Correct Option: B
Explanation:

Telescopes objective lenses have large apertures so that more number of light rays coming from object should enter and have greater resolution.

The length of an astronomical telescope for normal vision is _______.

  1. $-\displaystyle\frac{f _o}{f _e}$

  2. $-f _o\times f _e$

  3. $\displaystyle\frac{f _e}{f _o}$

  4. $f _o+f _e$


Correct Option: D
Explanation:

To get a magnified image of an object at infinity the image formed by objective lens will beat focus and if we want maximum magnification then the image formed by objective should be at focus of the eye piece.

Hence length of telescope =${ f } _{ o }+{ f } _{ e }$.
Here ${ f } _{ o }$ and ${ f } _{ e }$ are focal length of objective and eyepiece lens respectively.

In which of the following instruments is final image erect?

  1. Simple microscope

  2. Compound microscope

  3. Astronomical telescope

  4. Galilean telescope


Correct Option: A,D
Explanation:

simple microscope is placed between the optic center and the focus and the image is erect, virtual and magnified.

For compound microscope -The final image is virtual, inverted and magnified.
The final image formed by an astronomical telescope is always virtual, inverted.
Galilean telescope is to produce a virtual, erect image.



In which of the following instruments is the final image inverted?

  1. Projector

  2. Camera

  3. Microscope

  4. Telescope


Correct Option: C,D
Explanation:
For compound microscope -The final image is virtual, inverted and magnified.
The final image formed by an astronomical telescope is always virtual, inverted.
Camera and projector always form erect image.

The final image formed by an astronomical telescope is

  1. real and erect

  2. virtual and erect

  3. real and inverted

  4. virtual and inverted


Correct Option: D
Explanation:

An astronomical telescope is an optical instrument which is used to see the magnified image of distant heavenly bodies. The final image formed by an astronomical telescope is always virtual, inverted and magnified.

For the astronomical telescope, the focal length of objective lens is ${f} {o}$ and the eye piece lens is ${f} _{e}$. Then the tube length of the telescope is ____

  1. $L\ge { f } _{ o }-{ f } _{ e }$

  2. $L\ge { f } _{ o }+{ f } _{ e }$

  3. $L<{ f } _{ o }+{ f } _{ e }$

  4. $L\le { f } _{ o }-{ f } _{ e }$


Correct Option: B
Explanation:

For astronomical telescope
$\left| { v } _{ 1 } \right| ={ f } _{ o }$
$\left| { u } _{ 2 } \right| \le { f } _{ e }$
Probable answer would be (c) conceptually correct