Tag: physics

Questions Related to physics

The focal lengths of the objective and eyepiece of a telescope are 60cm and 5cm respectively.The telescope is focused on an object 360cm from the objective and the final image is formed at a distance of 30cm from the eye of the observer. The length of the telescope is

  1. 66.3 cm

  2. 86.3 cm

  3. 76.3 cm

  4. 96.3 cm


Correct Option: C
Explanation:

$f _o = 60cm$


$f _e = 5cm$

$r _e = 30cm$

$L = ?$

$u _o = 360cm$

$\dfrac {1}{v _o} + \dfrac {1}{360} = \dfrac {-1}{60}$

$\dfrac {1}{v _o} = \dfrac {-1}{60} + \dfrac {1}{360}$

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

  1. Projector

  2. Camera

  3. Microscope

  4. Telescope


Correct Option: C,D
Explanation:

The final image of the camera and projector is real because it is obtained or projected on a screen or a photographic film or a chip.

A simple microscope uses convex lens and the object is placed between the focus and the optical center, so that, an erect, virtual and enlarged image of the object is formed.

A telescope uses two co-axially placed convex lenses in such a way that the focus of objective lens is past the focus of the eye piece. The first lens or the objective lens produces a real and inverted image of the object to be observed and this real image formed acts as an object for the eye piece convex lens and is between the focus and the optical center, so that, an inverted, virtual and enlarged image of the object is formed.

Hence, the correct answers are OPTIONS C and D.  

A planet is observed by an astronomical reflecting telescope having an objective of focal length $16 m$ and an eye-piece of focal length $2 cm$. Then :

  1. the distance between the objective and the eye - piece is $16.02 m$

  2. the angular magnification of the planet is $800$

  3. the image of planet is erect

  4. the objective is larger than eye - piece


Correct Option: A,B,D
Explanation:

A telescope uses two co-axially placed convex lenses in such a way that the focus of objective lens is past the focus of the eye piece as evident here from the focal lengths of the objective lens and the eye piece. $ \therefore $ The objective lens is larger than eye piece.

Length of the tube is given as 
$ L = f _o + f _e = 16\ m + 2\ cm = 16.02\ m $

Angular magnification is given as:
$ m = \dfrac{f _o}{f _e} = \dfrac{1600}{2} = 800 $


Since, the first lens or the objective lens produces a real and inverted image of the object to be observed and this real image formed acts as an object for the eye piece convex lens and is between the focus and the optical center, so, an inverted, virtual and enlarged image of the object is formed. $ \therefore $ The final image is inverted. 

Hence, the correct answers are OPTIONS A,B and D.

An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of

  1. large focal length and small diameter

  2. large focal length and large diameter

  3. small focal length and large diameter

  4. small focal length and small diameter


Correct Option: B

For creating a document, you use ______command at File Menu.

  1. Open

  2. Close

  3. New

  4. Save


Correct Option: C
Explanation:

For creating a document you use new command at file menu to open new document. There is a bank document which is  opened and you can perform specific activities or provide ew data in that document.

The Word function that corrects text as you type is referred to as -.

  1. Auto Summarize

  2. Auto Insert

  3. Auto Correct

  4. Track Changes


Correct Option: C
Explanation:

The Word function that corrects text as you type is referred to as Auto Correct.

Text replacement, replace-as-you-type or autocorrect is an automatic data validation function commonly found in word processors and text editing interfaces for smartphones and tablet computers. Its principal purpose is as part of the spell checker to correct common spelling or typing errors, saving time for the user.

Choose AutoCorrect options for capitalization, spelling, and symbols. You can use the AutoCorrect feature to correct typos, capitalization errors, and misspelled words, as well as automatically insert symbols and other pieces of text.

Auto-correct is a type of software program that identifies misspelled words, uses algorithms to identify the words most likely to have been intended, and edits the text accordingly. Auto-correct is commonly a feature included in word processors and messaging platforms of various types. Apple, Google and Microsoft products all have their own versions of auto-correct programs. 

You can start Microsoft Word by using _______button.

  1. New

  2. Start

  3. Program

  4. Control Panel


Correct Option: C
Explanation:

You can start Microsoft word by using program button. 

Microsoft Office is an example of a

  1. closed-source software

  2. open-source software

  3. horizontal-market software

  4. vertical-market software

  5. compiler


Correct Option: A
Explanation:

Microsoft Office is an example of a closed-source software.

Closed source (or proprietary software) means computer programs whose source code is not published. The source code is not shared with the public for anyone to look at or change. Closed source is not open source, but some software is neither, because open source also implies the freedom to redistribute.

Examples of closed source software for commercial use are Microsoft Office, Adobe Acrobat, McAfee anti-virus software, and so on. Examples of closed source software not distributed commercially would be proprietary software used to operate a proprietary operation at a bank or a factory.

Which type of file is created by Word Processing Programs?

  1. Database File

  2. Storage File

  3. Worksheet File

  4. Document File


Correct Option: D
Explanation:

Document File is created by Word Processing Programs.

A word processor is software or a device that allows users to create, edit, and print documents. It enables you to write text, store it electronically, display it on a screen, modify it by entering commands and characters from the keyboard, and print it. Of all computer applications, word processing is the most common.

Some of the functions of word processing software include: Creating, editing, saving and printing documents. Copying, pasting, moving and deleting text within a document. Formatting text, such as font type, bolding, underlining or italicizing.

It is important to incorporate word processing skills in the classroom. A balanced technology program combines a range of computer skills such as word processing, spreadsheet, presentation, Internet, database, graphics, and desktop publishing. ... Word processing is the composition, editing, and formatting of text.

Rahul has performed the following steps is MS-WORD $2010$.
- Move the mouse pointer to the top of vertical scroll bar.
- Click and drag the mouse from top to down when mouse pointed changes to 
- Release the mouse.
What would be the result of this action?

  1. Double underline would be applied to all the text in the document.

  2. The document will get divided into two parts.

  3. Snapshot of document will be captured.

  4. Line spacing will get increased.


Correct Option: B
Explanation:

The type of mouse printer shown in the given question statement is of 'Split'.You can also make this pointer active by going to:
$ Viewtab \rightarrow Window group \rightarroa Split$.