Posted by: merly | July 15, 2009

50 COMMON INTERVIEW QUESTIONS AND ANSWERS

Review these typical interview questions and think about how you would answer them. Read the questions listed; you will also find some strategy suggestions with it.

1. Tell me about yourself?
Ans : The most often asked question in interviews. You need to have a short statement prepared in your mind. Be careful that it does not sound rehearsed. Limit it to work-related items unless instructed otherwise. Talk about things you have done and jobs you have held that relate to the position you are interviewing for. Start with the item farthest back and work up to the present.

2. Why did you leave your last job?
Ans: Stay positive regardless of the circumstances. Never refer to a majorproblem with management and never speak ill of supervisors, co-workers or the organization. If you do, you will be the one looking bad. Keep smiling and talk about leaving for a positive reason such as an opportunity, a chance to do something special or other forward-looking reasons.

3. What experience do you have in this field?
Ans: Speak about specifics that relate to the position you are applying for. If you do not have specific experience, get as close as you can.

4. Do you consider yourself successful?
Ans:You should always answer yes and briefly explain why. A good explanation is that you have set goals, and you have met some and are on track to achieve the others.

5. What do co-workers say about you?
Ans: Be prepared with a quote or two from co-workers. Either a specific statement or a paraphrase will work. Jill Clark, a co-worker at Smith Company, always said I was the hardest workers she had ever known. It is as powerful as Jill having said it at the interview herself.

6. What do you know about this organization?
This question is one reason to do some research on the organization before the interview. Find out where they have been and where they are going. What are the current issues and who are the major players?

7. What have you done to improve your knowledge in the last year?
Try to include improvement activities that relate to the job. A wide variety of activities can be mentioned as positive self-improvement. Have some good ones handy to mention.

8. Are you applying for other jobs?
Be honest but do not spend a lot of time in this area. Keep the focuson this job and what you can do for this organization. Anything else is a distraction.

9. Why do you want to work for this organization?
This may take some thought and certainly, should be based on the research you have done on the organization. Sincerity is extremely important here and will easily be sensed. Relate it to your long-term career goals.

10. Do you know anyone who works for us?
Be aware of the policy on relatives working for the organization. This can affect your answer even though they asked about friends not relatives. Be careful to mention a friend only if they are well thought of.

11. What is your Expected Salary? A loaded question. A nasty little game that you will probably lose if you answer first. So, do not answer it. Instead, say something like, That’s a tough question. Can you tell me the range for this position? In most cases, the interviewer, taken off guard, will tell you. If not, say that it can depend on the details of the job. Then give a wide range.

12. Are you a team player?
You are, of course, a team player. Be sure to have examples ready. Specifics that show you often perform for the good of the team rather than for yourself are good evidence of your team attitude. Do not brag, just say it in a matter-of-fact tone. This is a key point.

13. How long would you expect to work for us if hired?
Specifics here are not good. Something like this should work: I’d like it to be a long time. Or As long as we both feel I’m doing a good job.

14. Have you ever had to fire anyone?
How did you feel about that? This is serious. Do not make light of it or in any way seem like you like to fire people. At the same time, you will do it when it is the right thing to do. When it comes to the organization versus the individual who has created a harmful situation, you will protect the organization. Remember firing is not the same as layoff or reduction in force.

15. What is your philosophy towards work?
The interviewer is not looking for a long or flowery dissertation here. Do you have strong feelings that the job gets done? Yes. That’s the type of answer that works best here. Short and positive, showing a benefit to the organization.

16. If you had enough money to retire right now, would you?
Answer yes if you would. But since you need to work, this is the type of work you prefer. Do not say yes if you do not mean it.

17. Have you ever been asked to leave a position?
If you have not, say no. If you have, be honest, brief and avoid saying negative things about the people or organization involved.

18. Explain how you would be an asset to this organization?
You should be anxious for this question. It gives you a chance to highlight your best points as they relate to the position being discussed. Give a little advance thought to this relationship.

19. Why should we hire you?
Point out how your assets meet what the organization needs. Do not mention any other candidates to make a comparison.

20. Tell me about a suggestion you have made?
Have a good one ready. Be sure and use a suggestion that was accepted and was then considered successful. One related to the type of work applied for is a real plus.

21. What irritates you about co-workers?
This is a trap question. Think real hard but fail to come up with anything that irritates you. A short statement that you seem to get along with folks is great.

22. What is your greatest strength?
Numerous answers are good, just stay positive. A few good examples: Your ability to prioritize, Your problem-solving skills, Your ability to work under pressure, Your ability to focus on projects, Your professional expertise, Your leadership skills, Your positive attitude.

23. Tell me about your dream job?
Stay away from a specific job. You cannot win. If you say the job you are contending for is it, you strain credibility. If you say another job is it, you plant the suspicion that you will be dissatisfied with this position if hired. The best is to stay genetic and say something like: A job where I love the work, like the people, can contribute andcan’t wait to get to work.

24. Why do you think you would do well at this job?
Give several reasons and include skills, experience and interest.

25. What are you looking for in a job?
See answer # 23

26. What kind of person would you refuse to work with?
Do not be trivial. It would take disloyalty to the organization, violence or lawbreaking to get you to object. Minor objections will label you as a whiner.

27. What is more important to you: the money or the work?
Money is always important, but the work is the most important. There is no better answer.

28. What would your previous supervisor say your strongest point is?
There are numerous good possibilities: Loyalty, Energy, Positive attitude, Leadership, Team player, Expertise,Initiativ e, Patience, Hard work, Creativity, Problem solver.

29. Tell me about a problem you had with a supervisor?
Biggest trap of all. This is a test to see if you will speak ill of your boss. If you fall for it and tell about a problem with a former boss, you may well below the interview right there. Stay positive and develop a poor memory about any trouble with a supervisor.

30. What has disappointed you about a job?
Don’t get trivial or negative. Safe areas are few but can include: Not enough of a challenge. You were laid off in a reduction Company did not win a contract, which would have given you more responsibility.

31. Tell me about your ability to work under pressure.
You may say that you thrive under certain types of pressure. Give an example that relates to the type of position applied for.

32. Do your skills match this job or another job more closely?
Probably this one. Do not give fuel to the suspicion that you may want another job more than this one.

33. What motivates you to do your best on the job?
This is a personal trait that only you can say, but good examples are: Challenge, Achievement, Recognition

34. Are you willing to work overtime? Nights? Weekends?
This is up to you. Be totally honest.

35. How would you know you were successful on this job?
Several ways are good measures: You set high standards for yourself and meet them. Your outcomes are a success. Your boss tell you that you are successful

36. Would you be willing to relocate if required?
You should be clear on this with your family prior to the interview if you think there is a chance it may come up. Do not say yes just to get the job if the real answer is no. This can create a lot of problems later on in your career. Be honest at this point and save yourself future grief.

37. Are you willing to put the interests of the organization ahead of your own?
This is a straight loyalty and dedication question. Do not worry about the deep ethical and philosophical implications. Just say yes.

38. Describe your management style ?
Try to avoid labels. Some of the more common labels, like progressive, salesman or consensus, can have several meanings or descriptions depending on which management expert you listen to. The situational style is safe, because it says you will manage according to the situation, instead of one size fits all.

39. What have you learned from mistakes on the job?
Here you have to come up with something or you strain credibility. Make it small, well intentioned mistake with a positive lesson learned. An example would be working too far ahead of colleagues on a project and thus throwing coordination off.

40. Do you have any blind spots?
Trick question. If you know about blind spots, they are no longer blind spots. Do not reveal any personal areas of concern here. Let them do their own discovery on your bad points. Do not hand it to them.

41. If you were hiring a person for this job, what would you look for?
Be careful to mention traits that are needed and that you have.

42. Do you think you are overqualified for this position?
Regardless of your qualifications, state that you are very well qualified for the position.

43. How do you propose to compensate for your lack of experience?
First, if you have experience that the interviewer does not know about, bring that up: Then, point out (if true) that you are a hard working quick learner.

44. What qualities do you look for in a boss?
Be generic and positive. Safe qualities are knowledgeable, a sense of humor, fair, loyal to subordinates and holder of high standards. All bosses think they have these traits.

45. Tell me about a time when you helped resolve a dispute ?
between others. Pick a specific incident. Concentrate on your problem solving technique and not the dispute you settled.

46. What position do you prefer on a team working on a project?
Be honest. If you are comfortable in different roles, point that out.

47. Describe your work ethic?
Emphasize benefits to the organization. Things like, determination to get the job done and work hard but enjoy your work are good.

48. What has been your biggest professional disappointment?
Be sure that you refer to something that was beyond your control. Show acceptance and no negative feelings.

49. Tell me about the most fun you have had on the job.
Talk about having fun by accomplishing something for the organization.

50. Do you have any questions for me?
Always have some questions prepared. Questions prepared where you will be an asset to the organization are good. How soon will I be able to be productive? and What type of projects will I be able to assist on? are examples.

And Finally Best of Luck Hope you will be succussful in the interview you are going to face in coming days.

“Never take some one for granted,Hold every person Close to your Heart because you might wake up one day and realise that you have lost a diamond while you were too busy collecting stones.” Remember this always in life.

Posted by: merly | December 23, 2008

extracting patterns in perl

In many applications we may need to extract certain numbers , characters or even a mixture of characters ans numbers from sentences….
the below code will help you

consider the below example

eg: id #23517348 – from reply

Our aim is to extract 23517348 from the above data

regex for extracting is:- /(\d+)/

=====================================
my $sub=$::FORM{desc’}; // suppose sub prints the data
id #23517348 – from reply

#print “$sub”;
$sub =~/(\d+)/;
print “$1″;

=======================
Output
=====
23517348

Posted by: merly | November 15, 2008

100 keyboard shortcuts

Here are 100 keyboard shortcuts to pace up your work and Impress others
CTRL+C (Copy)
CTRL+X (Cut)
CTRL+V (Paste)
CTRL+Z (Undo)
DELETE (Delete)
SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
CTRL while dragging an item (Copy the selected item)
CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
F2 key (Rename the selected item)
CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text in a document)
CTRL+A (Select all)
F3 key (Search for a file or a folder)
ALT+ENTER (View the properties for the selected item)
ALT+F4 (Close the active item, or quit the active program)
ALT+ENTER (Display the properties of the selected object)
ALT+SPACEBAR (Open the shortcut menu for the active window)
CTRL+F4 (Close the active document in programs that enable you to have multiple documents open simultaneously)
ALT+TAB (Switch between the open items)
ALT+ESC (Cycle through items in the order that they had been opened)
F6 key (Cycle through the screen elements in a window or on the desktop)
F4 key (Display the Address bar list in My Computer or Windows Explorer)
SHIFT+F10 (Display the shortcut menu for the selected item)
ALT+SPACEBAR (Display the System menu for the active window)
CTRL+ESC (Display the Start menu)
ALT+Underlined letter in a menu name (Display the corresponding menu)
Underlined letter in a command name on an open menu (Perform the corresponding command)
F10 key (Activate the menu bar in the active program)
RIGHT ARROW (Open the next menu to the right, or open a submenu)
LEFT ARROW (Open the next menu to the left, or close a submenu)
F5 key (Update the active window)
BACKSPACE (View the folder one level up in My Computer or Windows Explorer)
ESC (Cancel the current task)
SHIFT when you insert a CD-ROM into the CD-ROM drive (Prevent the CD-ROM from automatically playing)

Dialog Box Keyboard Shortcuts

CTRL+TAB (Move forward through the tabs)
CTRL+SHIFT+TAB (Move backward through the tabs)
TAB (Move forward through the options)
SHIFT+TAB (Move backward through the options)
ALT+Underlined letter (Perform the corresponding command or select the corresponding option)
ENTER (Perform the command for the active option or button)
SPACEBAR (Select or clear the check box if the active option is a check box)
Arrow keys (Select a button if the active option is a group of option buttons)
F1 key (Display Help)
F4 key (Display the items in the active list)
BACKSPACE (Open a folder one level up if a folder is selected in the Save As or Open dialog box)

Microsoft Natural Keyboard Shortcuts

Windows Logo (Display or hide the Start menu)
Windows Logo+BREAK (Display the System Properties dialog box)
Windows Logo+D (Display the desktop)
Windows Logo+M (Minimize all of the windows)
Windows Logo+SHIFT+M (Restore the minimized windows)
Windows Logo+E (Open My Computer)
Windows Logo+F (Search for a file or a folder)
CTRL+Windows Logo+F (Search for computers)
Windows Logo+F1 (Display Windows Help)
Windows Logo+ L (Lock the keyboard)
Windows Logo+R (Open the Run dialog box)
Windows Logo+U (Open Utility Manager)

Accessibility Keyboard Shortcuts

Right SHIFT for eight seconds (Switch FilterKeys either on or off)
Left ALT+left SHIFT+PRINT SCREEN (Switch High Contrast either on or off)
Left ALT+left SHIFT+NUM LOCK (Switch the MouseKeys either on or off)
SHIFT five times (Switch the StickyKeys either on or off)
NUM LOCK for five seconds (Switch the ToggleKeys either on or off)
Windows Logo +U (Open Utility Manager)

Windows Explorer Keyboard Shortcuts

END (Display the bottom of the active window)
HOME (Display the top of the active window)
NUM LOCK+Asterisk sign (*) (Display all of the subfolders that are under the selected folder)
NUM LOCK+Plus sign (+) (Display the contents of the selected folder)
NUM LOCK+Minus sign (-) (Collapse the selected folder)
LEFT ARROW (Collapse the current selection if it is expanded, or select the parent folder)
RIGHT ARROW (Display the current selection if it is collapsed, or select the first subfolder)

Shortcut Keys for Character Map

After you double-click a character on the grid of characters, you can move through the grid by using the keyboard shortcuts:
RIGHT ARROW (Move to the right or to the beginning of the next line)
LEFT ARROW (Move to the left or to the end of the previous line)
UP ARROW (Move up one row)
DOWN ARROW (Move down one row)
PAGE UP (Move up one screen at a time)
PAGE DOWN (Move down one screen at a time)
HOME (Move to the beginning of the line)
END (Move to the end of the line)
CTRL+HOME (Move to the first character)
CTRL+END (Move to the last character)
SPACEBAR (Switch between Enlarged and Normal mode when a character is selected)

Microsoft Internet Explorer Navigation

CTRL+B (Open the Organize Favorites dialog box)
CTRL+E (Open the Search bar)
CTRL+F (Start the Find utility)
CTRL+H (Open the History bar)
CTRL+I (Open the Favorites bar)
CTRL+L (Open the Open dialog box)
CTRL+N (Start another instance of the browser with the same Web address)
CTRL+O (Open the Open dialog box, the same as CTRL+L)
CTRL+P (Open the Print dialog box)
CTRL+R (Update the current Web page)
CTRL+W (Close the current window)

This may come in handy someday. Good reason to own a cell phone:

If you lock your keys in the car and the spare keys are at home, call

someone at home on their cell phone from your cell phone.

Hold your cell phone about a foot from your car door and have the person

at your home press the unlock button, holding it near the mobile phone on

their end. Your car will unlock.

Saves someone from having to drive your

keys to you. Distance is no object. You could be hundreds of miles away,

and if you can reach someone who has the other “remote” for your car, you

can unlock the doors (or the trunk).

Posted by: merly | June 21, 2008

How to disable a STOLEN mobile phone?

To check your Mobile phone’s serial number, key in the following digits on your phone:

* # 0 6 #

A 15 digit code will appear on the screen. This number is unique to your

handset. Write it down and keep it somewhere safe. when your phone get

stolen, you can phone your service provider and give them this code. They

will then be able to block your handset so even if the thief changes the

SIM card, your phone will be totally useless.

You probably won’t get your phone back, but at least you know that whoever stole it can’t use/sell it either.

Posted by: merly | May 24, 2008

Scan your books online

How is the idea?

Scanning photos online for free.

Requirements

1.An Email account

2.A digital camera/ Camera phone not less than 2Megapixel.

Take photos,transfer to computer,attach send to Scanr.

Given below is another site Qipit.

Qipit stores up to 100 scanned documents in your account for free, where you can make them public and tag them, too. When you sign up for Qipit, optionally register your cameraphone’s make and model, and the app will tell you what it can do with images from it (whiteboards, hand-written notes and/or printed documents.)

Advantage is that it even works on low resolution phones(1.3 MP).

Posted by: merly | May 15, 2008

How to Lock windows folders without any software

How to Lock windows folders without any software

We are assuming that the name of the folder to be renamed is HideMePlease and it is located in D Drive, thereby making the path to the folder as

Disc D:\

Step I


The trick is pretty simple, If you rename the folder ( in our case
HideMePlease) to HideMePlease.{21EC2020-3AEA-1069-A2DD-08002B30309D}
When this renaming of the folder is done, windows by default makes
it point to the control panel. Upon clicking on the folder after
renaming, Control Panel is displayed.
To get your folder back to the original one, rename it back to HideMePlease.

In order to make the entire process simple and clean,
i would suggest that you make two batch files (files ending with .bat
extension). One file for hiding/locking the folder; the other for
getting it back/unlocking it.
Step II

1.) The batch file for hiding the folder can be named as:
Hide.bat
2.) Open notepad/your favorite text editor and type in this
//THIS FILE SHOULD BE PLACED IN d:\
REN HideMePlease HideMePlease.{21EC2020-3AEA-1069-A2DD-08002B30309D}
Step III


1.) The batch file for unlocking the folder can be named as
Recover.bat
2.) Open notepad/your favorite text editor and type in this
//THIS FILE SHOULD BE PLACED IN D:\
REN HideMePlease.{21EC2020-3AEA-1069-A2DD-08002B30309D} HideMePlease
IT IS A VERY GOOD TRICK AND WOULD COME HANDY WHEN YOU HAVE TO HIDE YOUR PERSONAL INFO FROM OTHERS!

Posted by: merly | May 14, 2008

Security in php

Posted by: merly | May 14, 2008

Cascading style sheets(CSS)


Cascading style
sheets are a new way of formatting your page layout, text, fonts, images, and almost anything you put on the page.They allow you to position things on your page down to the exact pixel. Also, if a style is declared in the head section of a page, a change to the style changes the style on the entire page.

What is CSS?

* CSS stands for Cascading Style Sheets
* Styles define how to display HTML elements
* Styles are normally stored in Style Sheets
* Styles were added to HTML 4.0 to solve a problem
* External Style Sheets can save you a lot of work
* External Style Sheets are stored in CSS files
* Multiple style definitions will cascade into one

Suppose that you created a style for a heading tag, <H1>. In your style, you set the color of your H1 tags to red. Now if you have 10 H1 tags on the page, and decide you would rather have your headings be blue, you would no longer need to go back and change the font color for each heading. All you have to do is change the style of your H1 tags from the color red to blue. Changing the style once will adjust all of your H3 tags and they will now be all blue instead of red, with alot less work.

Syntax

The CSS takes the following syntax

selector {property: value}

eg:-body {color: blue}

This can be applied to a group also
h1,h2
{
color: #000000;
}
Adding Styles to Elements with Particular Attributes

input[type="text"] {background-color: red}

The id Selector

You can also define styles for HTML elements with the id selector. The id selector is defined as a #.

The style rule below will match the element that has an id attribute with a value of “black”:

#black{color: black}

The style rule below will match the p element that has an id with a value of “para1″:

p#para1
{
text-align: center;
color: red
}

Comments in CSS

/* This is a comment */
p
{
text-align: center;

}

Inline Styles:

Inline styles are added directly to the element to be styled with the style attribute:

<p style=”color: red;”>

Inline styles are CSS styles that are applied to one element using the style attribute.

1. We write the style properties all one line .then we separate multiple properties with a semi-colon

eg:- background:#112344; color:#223555; border: solid black 1px;

2. Now you place that line of styles inside the style attribute of the element you want styled.

<p style =” background:#112344; color:#223555; border: solid black 1px;”>
Advantages and disadvantages of Inline Styles

Advantage

1) Inline styles have the highest precedence because of the cascade.

Disadvantages

1)They can over-ride things you didn’t intend them to do as they are most specific in cascade.

2)It’s impossible to style pseudo-elements and -classes with inline styles. For example, with external and internal style sheets, you can style the visited, hover, active, and link color of an anchor tag. But with an inline style all you can style is the link itself, because that’s what the style is on.

External style sheets

External style sheets (CSS) allow you to use one style sheet on multiple Web pages – so when you change the look for your site, you change the CSS in one.

Advantages and Disadvantages of External Style Sheets

Advantages

1)Since External style sheets are written in a single page it is easy to change the style and look of websites without much trouble.You need to make changes only in a single page and to a single portion.

2)To use the styles effectively we can group them easily.

Disadvantages

* External style sheets can increase the download time, if they are extremely large.

* If you only have a small number of styles, they can increase the complexity of your site.

* Like with table rendering, you have to wait until the entire style sheet is loaded before the page can display.

* External style sheets get big very quickly as it’s hard to tell when a style is no longer in use, because it’s not deleted when the page is removed.

LINKING TO PAGE

Each page which uses CSS must link to the style sheet using the <link> tag. The <link> tag goes inside the head section:

Your style sheet should be saved with a .css extension

Suppose that style.css is the name of the page where you put your styles.

<head>
<link rel=”stylesheet” type=”text/css”
href=”style.css” />
</head>

The browser will read the style definitions from the file style.css and format the document according to it.
body { background : #FFFFFF;}
p {margin-left: 20px}

Internal style sheets

An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section by using the <style> tag, like this:

<head>
<style type=”text/css”>

p {margin-left: 20px}

body {background : #FFFFFF;}
</style>
</head>

Multiple Style Sheets

A group of properties can be applied to a tag

eg:-body {
background : #FFFFFF;
border: #000000 ;
border-style: solid;
border-width: 0px;
padding: 10px ;
vertical-align: middle ;
text-align: center;
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
font-weight: 400 ;
color: #000000;
font-size:6;

}
Inside the tables for a all columns or rows you can specify the styles

td {
empty-cells : show;
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 13px;
font-weight: 400 ;
color: #000000;
text-align: center;
}

Posted by: merly | May 9, 2008

SCIENTIFIC LEMON Battery

The penny

: Any copper coin will work. (Canadian pennies from 1960 – 2001 all worked)

www.NidoKidos.Org

Creating the battery
: Insert a penny into a cut on one side of the lemon. Push a galvanized nail into the other side of the lemon.
The nail and penny must not touch.

www.NidoKidos.Org

This is a single cell of a battery. The zinc nail and the copper penny are called electrodes.

The lemon juice is called electrolyte.
All batteries have a “+” and “-” terminal. Electric current is a flow of atomic particles called electrons. Certain materials , called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons will flow from the “-” electrode of a battery, through a conductor, towards the “+” electrode of a battery.
Volts (voltage) is a measure of the force moving the electrons. (High voltage is dangerous!)

www.NidoKidos.Org

I have connected a volt meter to our single cell lemon battery. The meter tells us this lemon battery is creating a voltage of 0.906 volts.
Unfortunately this battery will not produce enough current (flowing electrons) to light a bulb.

www.NidoKidos.Org

To solve this problem we can combine battery cells to create higher voltages. Building more lemon batteries and connecting them with a metal wire from “+” to “-” adds the voltage from each cell.
www.NidoKidos.Org

The two lemon batteries above, combine to produce a voltage of 1.788 volts. This combination still does not create enough current to light a small bulb. Note the red wire connecting the batteries is joined from “+” (penny) to “-” (galvanized nail).

www.NidoKidos.Org

Four lemon batteries create a voltage of 3.50 volts. We should be able to light up a small device like an LED (Light Emitting Diode).
Note the connecting wires go from “+” to “-” on each battery.


www.NidoKidos.Org

LED

To turn on an LED you must determine the “+” and “-” connections. If you look closely at the red plastic base of an LED you will notice a “flat” spot (indicated by arrow above). The wire that comes out beside the flat spot must connect to the “-” side of a battery, the other wire to the “+” side.


Important information about LEDs
: LEDs are designed to work at very low voltages (~ 2V) and low currents. They will be damaged if connected to batteries rated at over 2 volts. LEDs require resistors to control current when used with batteries rated at over 2 volts. Lemon batteries produce low current. It is OK to connect an LED to a lemon battery.


www.NidoKidos.Org

In the above image, electrons flow from the “-” (nail) end of our lemon battery through the LED (making it glow) then back to the “+” (penny) end of the battery. This is an electronic circuit. The LED glows dimly with this configuration.

www.NidoKidos.Org


Improving your battery.

The quality of the copper and zinc can be a problem for a battery like this. Pennies in particular are rarely pure copper.
Try substituting a length of 14 gauge copper wire (common house wire) for the penny. Experiment with different lengths and configurations of electrodes. Other sources of zinc and copper may be found in the plumbing supply department of a hardware store.

The first battery was created in 1799 by Alessandro Volta . Today batteries provide the power for an amazing variety of devices, everything from flashlights to robots, computers, satellites and cars. Inventors and researchers continue to improve the battery, designing batteries that last longer and that are more friendly to our environment.

Understanding how batteries actually work requires a knowledge of chemistry. The most important factor in battery design is the electrical relationship between the two metals used in the battery. Some metals give electrons away while other metals accept extra electrons. Chemists have investigated metals and created an “electric potential” table comparing different metals.

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