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

Which of the following is true for a telescope?

  1. Final image is real and inverted.

  2. It increases the size of the object.

  3. It increases the angle subtended by image at the eye of the observer.

  4. Smaller telescopes are more powerful
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Telescope increases the visual angle of an object considerably and hence it allows to study the details of the objects carefully. The final image is actually much smaller than the object itself. 

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

In an astronomical telescope the focal lengths of objective and eyepiece should respectively be :

  1. large and small

  2. small and large

  3. equal

  4. too small are too large
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In an astronomical telescope, two convex lenses are used for different focal lengths. In which the lens with large focal length is an objective lens which is used to see large distance objects like stars or planets and the one with small focal is eyepiece. Hence correct option is A.

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

While viewing a distant object with telescope a housefly sits on objective lens. Then which of the following is the correct statement :

  1. housefly will be seen enlarged in image

  2. housefly will be seen reduced in image

  3. intensity of image will be decreased

  4. intensity of image will be increased
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When housefly sits on the objective lens, light intensity will fall at objective because housefly will stop the light to fall on the objective. So, intensity of the image is decreased. Hence correct option is C.

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

First adjustment of a spectrometer is :

  1. focusing the distant object

  2. focusing the cross wires

  3. focusing the slit

  4. focusing near objects
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

First we look through the telescope at any light - coloured surface and push the eyepiece in and out until we can see the cross-wires sharply, without straining our eyes, So, first adjustment in a spectrometer is focusing of the cross wires.

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

Large aperture objective is used in telescopes as it helps in

  1. increasing the brightness of image

  2. reducing image size

  3. increasing field of view

  4. increasing intensity by gathering more light
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation

The larger the objective, the more light the telescope collects and increases the brightness of image .

The field of view of the telescope decreases as the aperture increases, but the resolving power increases.
The objective lens of a telescope forms an real image of the night sky, the size of that image is in proportion to the focal length of the objective lens. It increases with increase in size of objective lens.

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

Large astronomical telescopes always use as objective

  1. lens

  2. mirror

  3. combinations of lenses

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Large astronomical telescopes always use combination of lens as objective because
(1)To minimize spherical aberration.
(2)To maximize the amount of light ray entering the telescope.
(3)To optimize the quality of image.
Multiple choice physics observing space: telescopes space research and satellites space travel space exploration and forms of light

In astronomical telescope, the final image is formed at:

  1. the least distance of distinct vision

  2. the focus of objective lens

  3. the focus of the eye lens

  4. beyond the focal length of eyepiece.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In astronomical telescope, the image formed by objective $I _1$ is real and inverted. It is formed at focus of objective lens. $I _1$ is placed between the focal length of eyepiece and the lens. Hence, it forms a virtual image beyond the focal length of eyepiece.

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 mircoscope

  2. Compound mircoscope

  3. Astronimical telescope

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A simple microscope is magnifying glass, an ordinary double convex lens having a short focal length that produces virtual and erect image.

rather a Compound microscope and astronomical telescope produces virtual and final inverted image. hence correct option is A.