“As this is normally done, the double-slit experiment simply measures the coherence of light rather than changing it,” Pacifici said. “But by introducing surface plasmon polaritons, Young’s double slits become a tool not just for measurement but also modulation.”

At first glance, interactive whiteboards look exactly the same as normal whiteboards. But looking closer reveals that they are unique and an exciting tool to use in the classroom and in business. Interactive whiteboards can be seen as input and output devices.

Often you will need additional software or hardware to make sure that your input and output devices can communicate with your computer. In most cases, your hardware will require a device driver to make sure that the commands it sends to and receives from your computer will be interpreted correctly.

This initial proof-of-concept work was done at the micrometer scale, but Pacifici and Li say there’s no reason why this couldn’t be scaled up for use in a variety of settings.

3.Interactive whiteboards allow learners to become part of the learning process by making them active participants in their lessons.

There are many factors that can affect the quality of the prints that come out of a printer. The most important factor is the resolution, which is measured in dots per inch (dpi). As you learned in the section on scanners, dpi measures how many dots there are in a square inch of an image and the higher the dpi is, the better the image quality will be.

Table 2.2 lists the quality specifications you should look for when buying a new display device and gives a brief explanation of each specification.

There are some display devices that act as both input and output devices; touchscreens and interactive whiteboards are examples of these types of devices.

One of the study’s key results is the strength of the modulation they achieved. The technique is able to modulate coherence across a range from 0 percent (totally incoherent) to 80 percent (nearly full coherent). Modulation of such strength has never been achieved before, the researchers say, and it was made possible by using nanofabrication methods that allowed to maximize the generation efficiencies of surface plasmon polaritons existing on both surfaces of the slitted screen.

5.2List two output devices that Thomas’s learners can use for their class projects. Also mention what equipment Thomas would need to connect each of these devices to a computer. (4)

Interactive whiteboards allow users to interact with the data that is displayed. By using a mouse or even your finger, you can drag, click and copy items. You can use your finger or the special pens to write notes, highlight sections or make comments. Anything that is done on the whiteboard can then be saved and shared.

“Coherence, like color and polarization, is a fundamental property of light,” said Domenico Pacifici, an associate professor of engineering and physics at Brown and coauthor of the research. “We have filters that can manipulate the color of light and we have things like polarizing sunglasses that can manipulate polarization. The goal with this work was to find a way to manipulate coherence like we can these other properties.”

Colour depth is also known as bit depth and refers to the number of bits used to indicate the colours of a single pixel. The higher the bit number, the better the colour depth. You can see this in Figure 2.1.

Storage devices are the computer components designed to keep (or store) data. This data can be the information needed to make the computer function, such as the operating system or basic input/output system (BIOS), or data created by the user, such as images, documents, text files and so on.

In this unit you will focus on interactive whiteboards and displays and the advantages, disadvantages and limitations of each of them. You will also learn about the factors determining the quality of display devices and printers, as well as the wireless technology needed for these devices to operate correctly.

In printers, dpi measures how well the printer can match the pixels per inch (ppi) of a digital image or text. If the printer can match the ppi exactly, the image will come out crisp and clear and will look the same when it is printed and when it is on screen. The problem comes in when the printer cannot match the ppi, so the image quality goes down.

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Wireless printers can be connected to multiple devices on the same wireless network, meaning that all the people in a specific area have access to the printer. Wireless printers can also connect to smartphones and tablets, so users can connect to them directly. However, since anyone can access a wireless printer, there are some safety and privacy concerns surrounding them.

Most operating systems also have a set of standard device drivers installed for things such as computer mice, keyboards and hard drives (internal and external). These devices are often referred to as plug-and-play devices.

Device drivers are software programs that are separate from the device. They are either given on a disk or downloaded from the manufacturers’ websites. Your OS will use a device’s driver to communicate with the device. The driver will help the OS understand the information you give it through an input device or translate the information the computer sends to an output device so that it can display the information correctly.

Write True or False next to the question number. Correct the statement if it is FALSE. Change the underlined word(s) to make the statement TRUE. (You may not simply use the word NOT to change the statement.)

In the classic double-slit experiment, an opaque barrier is placed between a light source and a detector. The light passes through two parallel slits in the barrier to reach the detector on the other side. If the light shown on the barrier is coherent, the rays emanating from the slits will interfere with each other, creating an interference pattern on the detector — a series of bright and dark bands called interference fringes. The extent to which the light is coherent can be measured by the intensity of bands. If the light is incoherent, no bands will be visible.

We use this information to present the correct curriculum and to personalise content to better meet the needs of our users.

“The surface plasmon polaritons open up a channel for the light at each slit to talk to each other,” Li said. “By connecting the two, we’re able to change the mutual correlations between them and therefore change the coherence of light.”

PROVIDENCE, R.I. [Brown University] — Brown University researchers have demonstrated for the first time a method of substantially changing the spatial coherence of light.

Output devices form the last stage of the information processing cycle. These are devices that translate the information from the internal processing components of the computer and display them in a way that makes sense to a human user. This could be text, images, sounds or videos.

Thomas is a high-school teacher who teaches a small class of 15 learners. Some of Thomas’s learners have physical challenges that would make it difficult for them to interact with a traditional computer. Thomas therefore has to think of what types of extra input and output devices he will need to make this class project work.

Isa keyboard aninput or output device

4.3Mention two jobs that can benefit from using interactive whiteboards. Give an explanation for each of your answers. (4)

The image on the left is in 32-bit colour while the image on the right is in 8-bit colour. In the image on the left, the details in the background are sharper and the colour of the leaf is deeper and more vibrant compared to the image on the right.

An input device is any device that allows you to enter data into a computer and interact with it. Common input devices include keyboards, computer mice, touchpads and touchscreens. You also learned about the basics of digital cameras, scanners and readers such as radio-frequency identification (RFID), magnetic strip and OCR readers. Other input devices are video and audio input devices such as webcams and microphones, and biometric input devices such as fingerprint scanners.

Headsets and speakers are designed for audio output, with other output devices being fax machines, multifunction devices (which combine faxing, emailing and printing) and data projectors.

How quickly a printer can print is another indicator of the quality of a printer. This is measured in pages per minute (or ppm) and the higher the ppm, the faster the printer prints. Laser printers will always have a higher ppm than inkjet printers because of the different ways that they print.

In a finding that could have broad applications in optical devices, Brown University researchers have shown that they can transform incoherent light to almost fully coherent and vice versa.

A printer’s dpi is usually shown just like a screen’s resolution is shown, since it is a measure of how many dots can be made horizontally and vertically. For example, a printer’s dpi may be shown as 1 600 × 2 000.

These components, called storage media or storage devices, are any piece of computing hardware used to keep or store data files. They can hold and store information permanently or temporarily and can be internal or external.

There has also been a rise in the use of alternative input devices, such as fingerprint and face recognition to unlock your smartphone, and speech-to-type devices that are used by people with physical challenges.

“We’ve broken a barrier in showing that it’s possible to do this,” Pacifici said. “This clears the way for new two-dimensional beam shapers, filters and lenses that can manipulate entire optical beams by using the coherence of light as a powerful tuning knob.”

Scanneris input or output device

OCR can also be used to improve accessibility for physically challenged users. OCR scanners can work alongside text-to-speech devices to read printed text aloud. OCR scanners are also used in handheld barcode scanners.

“There had been some theoretical work suggesting that coherence modulation was possible, and some experimental results showing small amounts of modulation,” said Dongfang Li, a postdoctoral researcher in Brown’s School of Engineering and the study’s lead author. “But this is the first time very strong modulation of coherence has been realized experimentally.”

Plug-and-play devices are usually external devices but can also be some internal components of the computer (such as graphics cards). Examples of plug-and-play devices are headphones and speakers, computer mice, keyboards and USB storage devices.

Several factors determine a display device’s quality. These include resolution, aspect and contrast ratios and response time, as well as other factors. Less expensive devices usually have very high specifications in one area and low specifications in another. Devices that have a good balance of specifications are usually more expensive.

Display devices are a broad category of output devices that includes monitors (computer screens), smartphone screens and data projectors.

CCTVCamera input or output

The main function of a display device is to display the input you have given the computer to allow you to make choices and interact with programs and the operating system.

Internal storage media, such as hard drives and RAM, are inside a computer and part of it, while external hard drives and USB drives are outside a computer and can be removed easily and quickly.

How much a camera can zoom is determined by its focal length. The focal length is shown by a number and the times symbol (×). A zoom of 3× means that the longest focal length is 3× the distance of the shortest focal length.

Controlling coherence: New research shows how incoherent light can be made coherent and vice versa. Credit: Pacifici lab / Brown University

Printeris input or output device

3.Write True or False next to the question number. Correct the statement if it is FALSE. Change the underlined word(s) to make the statement TRUE. (You may not simply use the word NOT to change the statement.)

3.Write True or False next to the question number. Correct the statement if it is FALSE. Change the underlined word(s) to make the statement TRUE. (You may not simply use the word NOT to change the statement.)

There are a number of input devices that you can use with computers. Table 2.1 lists these devices, their uses, and their advantages and disadvantages.

In this unit, you will learn more about device drivers that you need to install yourself and plug-and-play devices. You will also look at the physical ways devices connect to your computer. Lastly, you will look at what OCR is and where it is used.

Lastly, the duty cycle also shows the printer’s quality. The monthly duty cycle indicates the maximum number of pages a printer can print in a month without it failing. A typical home printer will have a duty cycle of around 5 000 pages, while large business printers will have a duty cycle of around 200 000 pages per month.

Isa touchpad aninput or output device

5.3Explain one way in which physically challenged learners can benefit from OCR technology. Also mention what type of input and output device will be used. NOTE: Mention the benefit and the related physical challenge. (4)

The final quality factor is the dynamic range. This measures the range of light the scanner can read and use to produce a range of tones and colours.

Microphoneinput or output

In Grade 10, you learned that hardware is the physical components of a computer. This includes items such as the monitor (or screen), keyboard and mouse.

Coherence deals with the extent to which propagating electromagnetic waves are correlated with each other. Lasers, for example, emit light that’s highly coherent, meaning the waves are strongly correlated. The sun and incandescent light bulbs emit weakly correlated waves, which are generally said to be “incoherent”, although, more precisely, they are characterized by low yet measurable degrees of coherence.

2.Because the notes made on the whiteboard can be saved and shared, learners do not need to take notes during a lesson. This allows them to focus more on participation during the lesson.

The lens aperture is the maximum amount that the lens can open. The wider it opens, the more light it can take in, which means that you need less light to take a good picture.

Wireless audio devices, such as speakers and headphones, use Bluetooth to connect to the computer. These output devices give users more freedom of movement as they are not physically attached to their computers.

To do that, Li and Pacifici took a classic experiment used to measure coherence, Young’s double slit, and turned it into a device that can modulate coherence of light by controlling and finely tuning the interactions between light and electrons in metal films.

Output devices take the processed input from a computer and display it in a way that is easy for humans to understand. Screens are the main output devices of any computer. Liquid crystal displays (LCDs) and LED screens are the most popular types. Printers are another common type of output device. There are two main printer types, namely inkjet and laser printers.

CPUis input or output device

Teachers and other users also need to be trained in how to use interactive whiteboards correctly and teachers may have to spend extra time preparing proper interactive lessons to get the most out of them.

As you learned in Chapter 1, a computer works using the information processing cycle. Input devices are the key components of the first stage of the cycle, the input stage. Input devices are what we use to interact with a computer. These can be things such as keyboards and computer mice, touchpads and scanners. The combination of keyboard and mouse used to be the most common input device, but the rise of the smartphone has made the touchscreen the most popular and common input device in the modern age.

Interactive whiteboards can be used like traditional whiteboards but you need to use special pens (that contain no ink) to write or draw on them. What makes interactive whiteboards so special is that they can be linked directly to a computer and can display what is on the computer. The clue to what sets these apart from normal data projectors is given in the name.

Resolution is the amount of detail an image can hold and it is measured in pixels per inch (ppi) or dots per inch (dpi). These measurements show you how many dots or pixels are in a one-inch square (an inch is about 2,5 cm). The higher the ppi or dpi, the more information there is in the square. This means that the image will be of higher quality.

There are as many output devices as there are input devices and there will certainly be more in the future as the way we interact with computers changes. When you think about output devices, you no doubt think about screens and displays, printers (including 3D printers), speakers and headphones. But interactive whiteboards, data projectors and GPS devices are also output devices.

Some of the notable disadvantages of interactive whiteboards include the cost, training and time requirements. Most interactive whiteboards are incredibly expensive (in 2018, an interactive whiteboard cost about R6 100) and they need special equipment to work correctly.

OCR stands for optical character recognition and it is a software program designed to convert printed characters (such as those on a hard copy document) into digital text. This means that you can edit and search in a scanned document in a word-processing program. OCR is most commonly found in specialised scanners used for archiving or document management. You can also get handheld OCR scanners that allow you to quickly scan printed text into a digital format. OCR enhances traditional scanning, since it saves the documents as text and not as an image.

Wireless output devices use Wi-Fi, Bluetooth or near-field communication (NFC) to communicate with the computer. Wireless devices reduce the number of cables you need to connect them to each other. Some examples of wireless output devices are wireless printers and wireless headphones or speakers.

In essence, surface plasmon polaritons are able to create correlation where there was none, or to cancel any existing correlation that was there, depending on the nature of the light coming in and the distance between the slits.

A normal non-magnetic whiteboard (2 000 mm × 1 200 mm) cost about R1 750 in 2018. This is one of the biggest whiteboards available.

Isa monitor aninput or output device

1.Interactive whiteboards allow teachers to combine visual and auditory learning styles into one. This allows learners to absorb information in multiple formats.

To do that, the researchers used a thin metal film as the barrier in the double slit experiment. When the light strikes the film, surface plasmon polaritons — ripples of electron density created when the electrons are excited by light — are generated at each slit and propagate toward the opposite slit.

Choose a term/concept from Column B that matches a description in Column A. Write only the letter next to the question number (e.g. 1–J). (5)

Most input and output devices need to be connected to the computer in some way for them to work. Keyboards and computer mice need to be connected either with a wireless USB dongle or a wired USB connector. Monitors will need power cables as well as display connectors (such as HDMI or VGA cables). Printers and projectors can be connected to the computer with cables, USB dongles or Bluetooth connections.

In a paper published in the journal Science Advances, the researchers show that they can use surface plasmon polaritons — propagating electromagnetic waves confined at a metal-dielectric interface — to transform light from completely incoherent to almost fully coherent and vice versa. The ability to modulate coherence could be useful in a wide variety of applications from structural coloration and optical communication to beam shaping and microscopic imaging.