BASIC SHORTCUT KEYS

Shortcut Keys

Description

Alt + F

File menu options in current program.

Alt + E

Edit options in current program

F1

Universal Help in almost ever Windows program.

Ctrl + A

Select all text.

Ctrl + X

Cut selected item.

Shift + Del

Cut selected item.

Ctrl + C

Copy selected item.

Ctrl + Ins

Copy selected item

Ctrl + V

Paste

Shift + Ins

Paste

Home

Goes to beginning of current line.

Ctrl + Home

Goes to beginning of document.

End

Goes to end of current line.

Ctrl + End

Goes to end of document.

Shift + Home

Highlights from current position to beginning of line.

Shift + End

Highlights from current position to end of line.

Ctrl + Left arrow

Moves one word to the left at a time.

Ctrl + Right arrow

Moves one word to the right at a time.

MICROSOFT WINDOWS SHORTCUT KEYS

Shortcut Keys

Description

Alt + Tab

Switch between open applications.

Alt + Shift + Tab

Switch backwards between open applications.

Alt + Print Screen

Create a screen shot only for the program you are currently in.

Ctrl + Esc

Bring Up start menu.

Alt + Esc

Switch Between open applications on taskbar.

F2

Renames selected Icon.

F3

Starts find from desktop.

F4

Opens the drive selection when browsing.

F5

Refresh Contents.

Alt + F4

Closes Current open program.

Ctrl + F4

Closes Window in Program.

Ctrl + (the '+' key on the

keypad)

Automatically adjust the widths of all the columns in Windows

explorer

Alt + Enter

Opens properties window of Selected icon or program.

Shift + F10

Simulates right click on selected item.

Shift + Del

Delete programs/files without throwing into the recycle bin.

Holding Shift

Boot safe mode or by pass system files.

Holding Shift

When putting in an audio CD, will prevent CD Player from playing.

WINDOWS KEYBOARD SHORTCUTS

Below is a listing of Windows keys that can be used on computers running a Micr

osoft Windows

operating system and using a keyboard with a Windows key. In the below list of short

cuts, the Windows key is

represented by "WINKEY". If you are looking for Windows shortcut keys, see t

he above Microsoft Windows

shortcut key section

.

Shortcut Keys

Description

WINKEY + D

Brings the desktop to the top of all other windows.

WINKEY + M

Minimizes all windows.

WINKEY + SHIFT + M

Undo the minimize done by WINKEY + M and WINKEY + D.

WINKEY + E

Open Microsoft Explorer.

WINKEY + Tab

Cycle through open programs through the taskbar.

WINKEY + F

Display the Windows Search / Find feature.

WINKEY + CTRL + F

Display the search for computers window.

WINKEY + F1

Display the Microsoft Windows help.

.

Ctrl + U

Underline highlighted selection.

Ctrl + 5

Strikethrough highlighted selection.

Ctrl + P

Bring up the print dialog box to begin printing.

Ctrl + Z

Undo last action.

Ctrl + F9

Minimize current window.

Ctrl + F10

Maximize currently selected window.

Ctrl + F6

Switch between open workbooks / windows.

Ctrl + Page up

Move between Excel work sheets in the same Excel document.

Ctrl + Page down

Move between Excel work sheets in the same Excel document.

Ctrl + Tab

Move between Two or more open Excel files.

Alt + =

Create a formula to sum all of the above cells

Ctrl + '

Insert the value of the above cell into cell currently selected.

Ctrl + Shift + !

Format number in comma format.

Ctrl + Shift + $

Format number in currency format.

Ctrl + Shift + #

Format number in date format.

Ctrl + Shift + %

Format number in percentage format.

Ctrl + Shift + ^

Format number in scientific format.

Ctrl + Shift + @

Format number in time format.

Ctrl + Arrow key

Move to next section of text.

Ctrl + Space

Select entire column.

Shift + Space

Select entire row.

WORD SHORTCUT KEYS

See our Microsoft Word page for additional help and information.

Shortcut Keys

Description

Ctrl + A

Select all contents of the page.

Ctrl + B

Bold highlighted selection.

Ctrl + C

Copy selected text.

Ctrl + X

Cut selected text.

Ctrl + P

Open the print window.

See our Microsoft Internet Explorer page for additional help and information.

Shortcut Keys

Description

Alt + Left Arrow

Back a page.

Alt + Right

Arrow

Forward a page.

F5

Refresh current page / frame.

F11

Display the current website in full screen mode. Pressing F11 again will exit t

his mode.

Esc

Stop page or download from loading.

Ctrl + Enter

Quickly complete an address. For example, type computer hope in the address bar

and press CTRL + ENTER to get http://www.computerhope.com.

Ctrl + N

Open New browser window.

Ctrl + P

Print current page / frame.

Spacebar

Moves down a page at a time.

Shift + Spacebar

Moves up a page at a time.

FRONTPAGE SHORTCUT KEYS

See our Microsoft FrontPage page for additional help and information.

Shortcut Keys

Description

Ctrl + C

Copy selected text.

Ctrl + X

Cut selected text.

Ctrl + P

Paste selected text.

Ctrl + K

Create a hyperlink.

Ctrl + B

Bold highlighted selection.

Ctrl + I

Italic highlighted selection.

Ctrl + U

Underline highlighted selection.

Ctrl + L

Left align the text.

Ctrl + R

Right align the text.

Ctrl + E

Center the text.

Ctrl + /

Display HTML tags.

Ctrl + S

Save document.

Ctrl + Tab

Switch between open web pages.

Ctrl + Ins

Enter Line break.

Ctrl + Enter

Move cursor above or below a table.

Ctrl + Shift + B

Preview in web browser window.

Ctrl + Shift + <

Decrease font size.

Ctrl + Shift + >

Increase font size.

Ctrl + Del

Deletes word to right of cursor.

Ctrl + Backspace

Deletes word to left of cursor.

OUTLOOK SHORTCUT KEYS

See our Microsoft Outlook page for additional help and information.

Shortcut Keys

Description

Alt + S

Send the e-mail

Ctrl + C

Copy selected text.

Ctrl + X

Cut selected text.

Ctrl + P

Paste selected text.

Ctrl + K

Complete the name and/or e-mail being typed in the e-mail address bar.

Ctrl + B

Bold highlighted selection

Ctrl + I

Italic highlighted selection

Ctrl + U

Underline highlighted selection

Ctrl + R

Reply to an e-mail.

Ctrl + F

Forward an e-mail.

Ctrl + N

Create a new e-mail.

Ctrl + Shift + A

Create a new appointment to your calendar.

Ctrl + Shift + O

Open the Outbox.

Ctrl + Shift + I

Open the Inbox.

Ctrl + Shift + K

Add a new task.

Ctrl + Shirt + C

Create a new contac

The biggest advantage of installing Windows using USB flash drive is speed: It installs Windows just about 15 minutes approximately. Moreover, traditional optical disks (DVDs) get damaged upon use and time, so there is no surety whether it will successfully install Windows on your PC or not. USB flash drive gives you great ease and guarantee!
To install Windows 7 or 8 from USB flash drive, you will require:
1) A USB flash drive with 4 GB or more storage capacity.
2) Windows 7 or Windows 8 installation files.

Click Here to Download This Guide to Your Computer

If the PDF file opens in your browser, click Control+S to save the file to your computer.

Follow these simple steps to install Windows from a USB drive:
1. Insert the USB flash drive to your computer. Copy any important data from flash drive to your PC.
2. Open Command Prompt with administrator rights- for which either you may type cmd in Start menu search box and hit Ctrl+ Shift+ Enter or Go to Start menu > All programs > Accessories, right click on Command Prompt and select Run as administrator.
3. Type ‘DISKPART‘ and hit enter. You’ll see DISKPART> prompt on screen.
4. Type ‘LIST DISK‘ and you’ll have a list of disks in your PC. Look for the disk number of your USB flash drive. Let’s assume that your disk drive number is ‘Disk 1′. ’Disk 0′ might be your hard drive. If you have Disk 2 as your USB flash drive then use Disk 2.


5. Type below commands one by one:

SELECT DISK 1
CLEAN
CREATE PARTITION PRIMARY
SELECT PARTITION 1
ACTIVE
FORMAT FS=NTFS
(Formatting may take a few seconds)
ASSIGN
EXIT

6. Now, still in Command prompt, locate ‘boot‘ folder in your Windows installation folder you have on your hard disk or DVD drive.
For example, assume that your Windows installation files are located at folder D:\Windows7 in your hard disk, type the following commands:

D:\
CD Windows7
CD boot

7. Type following command:

BOOTSECT.EXE /NT60 K:

Here, K:, for example, is your USB drive letter. You’ll see below message:

8. Finally, copy your Windows 7 or Windows 8 installation files to the USB flash drive.
9. Your USB drive is ready to boot and install Windows 7 or 8. Only thing you now need to change the boot priority at the BIOS to USB from the HDD or DVD drive. I think no explanation is required for this as it’s just the matter of changing the boot priority or enabling the USB boot option in the BIOS.
If you are still not able to boot after following this guide, this only means that you haven’t set the BIOS priority to USB.

Full Forms

Full Forms

* CD - Compact Disk.
* DVD - Digital Video Disk.
* AM - Ante Meredian.
* PM - Post Meredian.
* AD - AnnoDomini.
* BC - Before Christ .
* FM - Frequency Modulation.
* GPRS - General Packet Radio
Service.
* USB - Universal Serial Bus.
* www - World Wide Web.
* Http - Hypertext Transfer
Protocol.
* HTML - Hypertext Mark
Language.
* LAN - Local Area Network.
* SIM - Subsciber Identity
Module .
* GSM - Global System for Mobile.
* WLAN - Wireless Local
Network.
* SQL - Structured Query
Language.
* XSS/CSS - Cross Site Scripting
* LFI - Link Fragmentation and

Apple iPad 

 

ntroduction

Wait, did hell just freeze over? Maybe a couple of degrees cooler? Rumors of a mini version of the iPad had been laughed at, dodged and denied - not necessarily in that order and often all at once. But here it is - the iPad mini is finally a reality. It caused due measures of excitement and perhaps a bit of disappointment. Yet, in typical Apple fashion, it's an excellent piece of hardware. In short, it's a polarizing device that may as well be the next best-selling tablet.

Apple iPad mini official images
You have to hand it to Apple's R&D team - they know how to design hardware. The iPad mini is super thin and light, with a cool aluminum shell. Sure, they swore they'd never make a 7" tablet and the truth is they still haven't - the 7.9" screen of the mini offers 36% more real estate than the screens of the Google Nexus 7 and the Amazon Kindle Fire HD.
Less bezel on the left and right of the screen combined with the ~310g of weight make it reasonably comfortable to hold with one hand. Apple did make some compromises, which drew a lot of ire. Here's the summarized list of what's good and what's bad about the Apple iPad mini:

Key features

• Compact body: 200 x 134.7 x 7.2 mm
• 7.9" LED-backlit IPS LCD touchscreen, 768 x 1024 pixels; scratch-resistant, oleophobic coating
• Dual-band Wi-Fi 802.11 a/b/g/n connectivity, carrier-dependent hotspot support
• Optional 2G/3G GSM, CDMA, LTE connectivity (data only, separate models)
• Optional GPS with A-GPS support (for the 3G model only)
• Apple A5 SoC, dual-core Cortex-A9 @ 1GHz chipset
• 512MB of RAM
• PowerVR SGX543MP2 dual-core GPU
• iOS 6 with Siri, iCloud support and activation
• 16/32/64GB of inbuilt storage
• Weight of 308 grams (312 grams for the Wi-Fi + Cellular option)
• Bluetooth 4.0
• 16.3Wh battery
• Accelerometer, compass and three-axis gyro-sensor
• Compatible with every iPad and iPhone app without any modifications
• The base version costs less than a SIM-free iPhone 4, only $30 more than iPod touch
• 5MP auto-focus camera
• 1080p video recording at 30fps
• 1.2MP secondary camera capable of FaceTime calls, 720p recording
• Four and five-finger gestures
• 1080p TV-output with the Apple Digital AV Adapter (purchased separately for $49), 1080p video streaming
• Supports magnetic cases
• Lightning connector
• Stereo loudspeakers

Main disadvantages

• More expensive than 7" Android tablets, only $70 cheaper than iPad 2
• No Retina display, 162ppi only
• Same chipset as iPad 2, now two generations old
• iTunes still required for most of the content uploads
• Reflective screen struggles outdoors
• No standard USB port, Lightning accessories still rare and expensive
• No GPS receiver in the Wi-Fi version
• No memory card slot
• Lack of basic iOS apps - stocks, calculator, voice memos

The disadvantage list may seem longer than usual but most of the items there are general complaints that apply to virtually all Apple products, like the absence of a memory card slot. The way we see it, there are three main problems with the iPad mini - the (relatively) low-res screen, the old chipset and the price.
Apple products have so far effortlessly hit it big with users despite their perceived limitations compared to the competition. The new crop of iPads - the iPad 4 and iPad mini - already sold in the millions.

iPad mini in our office
The software - iOS 6 - should be very familiar to Apple users, but the hardware is new. It's not like the big iPads, which mostly varied in thickness, this one has been designed to comfortably hold in one hand and slip into a coat pocket.
Some analysts have gone as far as to say that the iPad mini will become the iPad - it's highly portable, capable enough and drawing on the vast resources of the Apple eco-system. And if you adjust for the "Apple tax", the mini isn't that expensive.

 

Sony Xperia Z

 

Introduction

Whether they had a point to prove to the ex or simply kept themselves busy to get over it, Sony were hard at work in the last year or so. They can look back at a prolific period, though somewhat lacking in brilliance. Keen to quickly build a lineup from scratch, the company was consciously avoiding fights that were impossible to win. Steering clear of the premium end, Sony positioned its flagship devices just below the Samsung Galaxies and the iPhones.

Sony Xperia Z official photos
Now with solid backup in the midrange, returning to the fiercest battle in the mobile market is Sony's top priority. The Xperia Z, which leads the charge, got us properly impressed in a recent hands-on and if it walks unscathed from a complete review, we'll know the Japanese have hit the form of their life. Sony is the first of the major manufacturers to bring 5 inches of 1080p goodness to the market, which not only is a morale booster, but will get cash registers chiming too.

Key features

• Quad-band GSM/GPRS/EDGE support; 3G with HSPA; LTE
• 5" 16M-color 1080p capacitive touchscreen with 441ppi pixel density; Bravia Mobile Engine 2
• Android OS v4.1.1 Jelly Bean with custom UI
• Quad-core 1.5 GHz Krait CPU, 2 GB RAM, Adreno 320 GPU; Qualcomm Snapdragon S4 Pro chipset
• 13 MP autofocus camera with LED flash and geo-tagging, HDR
• 1080p video recording @ 30fps with HDR mode, continuous autofocus and stereo sound
• 2.2 MP front-facing camera, 1080p video recording
• IP 57 certification - dust resistant and water resistant
• Wi-Fi a/b/g/n, Wi-Fi Direct and DLNA; Wireless TV out
• GPS with A-GPS, GLONASS
• 16GB of built-in storage; microSD card slot
• MHL-enabled microUSB port
• Bluetooth v4.0
• NFC
• Standard 3.5 mm audio jack
• Accelerometer and proximity sensor
• Active noise cancellation with dedicated mic
• Glass front and back panels

Main disadvantage

• Low contrast display with below-par viewing angles
• Non user-replaceable battery
• 13MP camera hardly any better than some competitors' 8MP units
• Feeble loudspeaker

The Sony Xperia Z is stuff geeks' dreams are made of, it's designed and built to the highest standard and has raw processing power to spare. IP57-certified - on top of that - for dust and water resistance, it's tougher than most competitors. High-end smartphones aren't quite fit for the beach or white water rafting, but the Xperia Z won't be at odds with your active lifestyle.

Sony Xperia Z studio shots
The Xperia Z seems to have all the best technology currently available under the hood, so no wonder it's been at or near the top of our interest chart ever since it was announced at CES. And now, just one week away from its European release, we are about to see how likely it is to stay there for a good while.

 

Apple iPhone 5 vs. Samsung Galaxy S III

 

 

ntroduction

When we review phones we try to put them in context, and tie everything up with a snapshot of the market and the closest alternatives. Now, we usually keep droids and iPhones separate because honestly they just don't mix. But every now and then, they just cannot be kept apart. Never mind the risk of explosion.

Apple iPhone 5 • Samsung Galaxy S III
So there you have it: the new iPhone 5 against the Samsung Galaxy S III. In case you're wondering why this has taken so long, we needed quality time with both phones - not just to get the reviews in, but actually use them day in, day out. Now we're ready to share our impressions and give you insights that will hopefully help decide which one is right for you.
The two phones are polar opposites in terms of design - starting from size, through the design language, to the OS philosophy, those two could hardly be more different.
Apple has everything tightly locked down. Perfection, as they see it, can only be achieved in their walled garden. With Android and Samsung there's little you're not allowed to tweak (but be careful what you wish for as the saying goes).
It's not a battle of light versus dark, it's a matter of values and beliefs - Zen-like perfection and simplicity versus nothing-is-off-limits freedom. Here's what kind of design choices that led to:

Apple iPhone 5 over Galaxy S III:

• Thinner, lighter, more compact
• More impressive build materials
• Sharper screen with better sunlight legibility and more accurate colors
• LTE on all models

Samsung Galaxy S III over iPhone 5:

• Bigger, higher-res screen
• NFC connectivity
• Standard USB port for data transfer and charging
• microSD card slot for (cheap) storage expansion
• Mass storage mode, USB Host functionality
• Native Google Maps
• 2GB RAM in some versions

The new iPhone is taller and thinner than its predecessor, but keeps the same screen width and pixel density, and makes sure the hand feel is not impaired. Apple also went with a brand new connector design - the Lightning port. The inconvenience of yet another standard aside, it is better in every way and has allowed Apple engineers to build a more compact phone.
Samsung, on the other hand, went all out - bigger this, more of that, let's get this in too. It adhered to industry standards and the Galaxy S III has a microSD card slot and a user-accessible battery, which makes extending the phone's life easier (e.g. expanding the storage or changing the battery when the old one starts showing its age).

Apple iPhone 5 and Samsung Galaxy S III going head to head
The differences in ideology are apparent in the software too - Apple's design is best executed by Apple, so they made their own maps. It's not an easy task and it will take years to get them right (it's how long it has taken their competitors to get where they are today).
Samsung on the other hand take advantage of Android's open, extendable design and piled on new features. There's barely a corner left in the OS that doesn't bear their mark.
We'll start by comparing the hardware of the Apple iPhone 5 and the Samsung Galaxy S III, with the performance of the two contenders in various real-life challenges to be examined after that.

Samsung Galaxy S3 on Jelly Bean

 

Flashing the Vralec Bootchain

The VRALEC bootchain is required prior to installing any custom recovery to your phone. So follow the following steps to install it:

• You must have already installed all the USB drivers for your phone.
• Boot the phone into ODIN download mode.
  In order to do so, power off your phone. Then press the ‘volume down’ and ‘home’ buttons and while keeping them pressed power on your phone. As soon as you see a warning screen, release the keys and then press the ‘volume up’ button and you will be in the ODIN download mode.
• Now click the PDA button in ODIN and select the VRALEC.bootchain.tar file you downloaded earlier.
• Click the start button and you will be done.

Installing Custom Recovery

• Now again boot into the ODIN download mode as you did earlier.
• In the PDA section, browse to the respective file that you downloaded earlier for the custom recovery of your choice, either ClockworkMOD or TWRP Recovery.
• Remember to uncheck the ‘auto reboot’ option. This is quite an important step.
• Now click start and wait till the process finishes.
• Once done, your screen will go black. Now immediately press the ‘power up’ and ‘home’ buttons. You need to be quick with this.

Unrooting and/or Unlocking Bootloader

• Now that you have entered the recovery mode of your phone, you will see the recovery menu.
• If not, reboot into the recovery mode.
• Go to the ‘install ZIP from SD card’ option.
• In the next menu click the ‘select ZIP’ option.
• Now choose the ZIP that you need to install depending on whether you just need to root or unlock bootloader or both on your phone. You had downloaded the respective ZIP in the beginning of this process.
• Install the ZIP and you will be done.

Restoring the Bootloader

• This step is optional and will be required if you need to go to the original settings and partitions of your phone as it was earlier.
• Boot your phone into ODIN download mode.
• Flash the VRBLK3 bootchain as you did earlier with VRALEC bootchain.
• After finishing the flashing process, your phone will be back to normal.

So, now you can root verizon samsung galaxy S3 on jelly bean that too very easily.

 

How to Upgrade Sony Ericsson Xperia U to Ice Cream Sandwich

 

 

 

Installing the ICS Firmware on Sony Xperia U ST25a or ST25i

• First of all you need to extract the firmware files that you have already downloaded. You would have noticed that the files are in a ZIP format. Extract them until you get a file with .ftf extension.
• Install the flashtool on your computer.
• Now browse to the directory of your computer to which the flashtool has been installed. Generally it is C:\Flashtool\firmwares. And then copy the firmware file that you have extracted in the previous step there.
• Now execute the flashtool utility as an administrator so that you have full access and permissions for its operations.
• If there are any Sony update services or Sony PC companion services running, you need to terminate them all. You may notice them in the notification area if they are running and exit them before you start the procedure.
• In the flashtool, you will notice a thunder icon as the one shown in the image below. Click it to begin the process.

• Soon you will be presented with a popup window that will ask you for the desired mode. In that window select the ‘Flash Mode’ by ticking it.
• Now press OK.
• Now you will see a firmware selection window in front of you. You need to browse to the directory where you had saved the firmware earlier, in case you had not saved in the flashtool firmware directory. Once you choose the desired firmware file, click OK.
• Now you need to choose the correct file from the options that you see next as the one shown in the image below:

• If you are using a ST25a, you need not modify any of the other options.
• But if you are using the ST25i, you need to tick the ‘exclude baseband’ option as shown in  the following image:

• In order to begin the installation process, click the OK button that you see at the bottom of the window as shown in the following image:

• If your phone is already connected to your PC, you need to disconnect it before you go further with the process.After you have disconnected the phone, switch it off.
• Now, wait for almost 30 seconds and then connect your phone to the PC while it is still switched off. While you connect the phone to PC, you are supposed to hold the volume down button.
• Though you will see a notification window telling you to disconnect your phone from your PC and to press and hold the back button, but you need to ignore it. So do not pay heed to this window and it will automatically disappear.
• Now the flash process will commence and you can see the progress in the progress bar on the bottom of flashtool window.
• During the process, do not use your phone or interrupt in between to avoid any damages or in the worst cases bricking your phone.
• Once the flashing is complete, turn your phone ON.
• It might take some time for the first boot and voila! You are now running ICS on your phone.

What Is WiFi?

 

A wireless network uses radio waves, just like cell phones, televisions and radios do. In fact, communication across a wireless network is a lot like two-way radio communication. Here's what happens:

1. A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.
2. A wireless router receives the signal and decodes it. The router sends the information to the Internet using a physical, wired Ethernet connection.

The process also works in reverse, with the router receiving information from the Internet, translating it into a radio signal and sending it to the computer's wireless adapter.
The radios used for WiFi communication are very similar to the radios used for walkie-talkies, cell phones and other devices. They can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and convert the radio waves back into 1s and 0s. But WiFi radios have a few notable differences from other radios:

 

SUN   RAY   ARE    HELPFUL

We all need some sun exposure; it's our primary source of vitamin D, which helps us absorb calcium for stronger, healthier bones. But it doesn't take much time in the sun for most people to get the vitamin D they need, and repeated unprotected exposure to the sun's ultraviolet rays can cause skin damage, eye damage, immune system suppression, and skin cancer. Even people in their twenties can develop skin cancer.

Most kids rack up a lot of their lifetime sun exposure before age 18, so it's important that parents teach their children how to enjoy fun in the sun safely. With the right precautions, you can greatly reduce your child's chance of developing skin cancer.

Facts About Sun Exposure

The sun radiates light to the earth, and part of that light consists of invisible ultraviolet (UV) rays. When these rays reach the skin, they cause tanning, burning, and other skin damage.
Sunlight contains three types of ultraviolet rays: UVA, UVB, and UVC.

1. UVA rays cause skin aging and wrinkling and contribute to skin cancer, such as melanoma. Because UVA rays pass effortlessly through the ozone layer (the protective layer of atmosphere, or shield, surrounding the earth), they make up the majority of our sun exposure. Beware of tanning beds because they use UVA rays as well as UVB rays. A UVA tan does not help protect the skin from further sun damage; it merely produces color and a false sense of protection from the sun.
2. UVB rays are also dangerous, causing sunburns, cataracts (clouding of the eye lens), and effects on the immune system. They also contribute to skin cancer. Melanoma, the most dangerous form of skin cancer, is thought to be associated with severe UVB sunburns that occur before the age of 20. Most UVB rays are absorbed by the ozone layer, but enough of these rays pass through to cause serious damage.
3. UVC rays are the most dangerous, but fortunately, these rays are blocked by the ozone layer and don't reach the earth.