Tag: physics

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Questions Related to physics

Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

The number of wavelengths in the visible spectrum is :

  1. $4000$

  2. $6000$

  3. $2000$

  4. $inifinite$
Reveal answer Fill a bubble to check yourself
D Correct answer
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
Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

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
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

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. $f _o+f _e$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

In which of the following instruments is final image erect?

  1. Simple microscope

  2. Compound microscope

  3. Astronomical telescope

  4. Galilean telescope
Reveal answer Fill a bubble to check yourself
A,D Correct answer
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.



Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

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

  1. Projector

  2. Camera

  3. Microscope

  4. Telescope
Reveal answer Fill a bubble to check yourself
C,D Correct answer
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.
Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

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. $L\le { f } _{ o }-{ f } _{ e }$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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