7th Maths

 

Chapter 1 Number System Intext Questions

1.Write the following integers in ascending order: -5,0,2,4, -6,10, -10

2.If the integers -15, 12, -17, 5, -1, -5, 6 are marked on the number line then the integer on the extreme left is _____ .

3.Complete the following pattern:
50, ______ 30, 20, ______, 0, -10, _______, _______, -40, ______, _______.

4.Write the given integers in descending order, -27, 19, 0, 12, -4, -22, 47, 3, -9, -35.

5.Say True or False.
(i) (-11) + (-8) = (-8) + (-11)
(ii) -7 + 2 = 2 + (-7)
(iii) (-33) + 8 = 8 + (-33)

UPS

 

What is a UPS device?

During power surges and failures, Uninterruptible Power Supply (UPS) devices keep computer systems and IT equipment safe and operational. An Uninterruptible Power Supply (UPS) provides battery backup power when the flow of electricity drops to an inadequate voltage, or if it stops. An uninterrupted power source is vital for the mission-critical environment. Depending on the size and technology of the UPS unit, backup power is provided for a specific period of time, until generators can be activated or network components can be properly shut down. When electricity flows adequately, computers and accessories are protected from damage. A UPS unit can help to shield a single device or an entire data centre effectively. 

Three types of UPS Technologies

Online Double Conversion Technology

An uninterruptible power supply using true online double conversion technology provides the highest level of power protection available. The Online UPS converts the 230V input AC mains supply to DC power, which is then used to charge the battery. The DC current flow is then fed through an inverter stage that reconstructs the 230V AC mains output. Because the AC output is completely regenerated, it will be completely free from any mains-borne interference such as spikes and voltage variations. The output voltage and frequency is controlled precisely, thus ensuring a clean and stable sine wave power output. Online UPS are able to withstand large fluctuations on the input voltage before transferring to battery power (typically 276V-184V) thus eliminating unnecessary battery discharges. Upon mains failure, transfer to battery power is seamless - no break. Online UPS also have various failsafe and self-diagnostic features that will instantly transfer the load onto mains power if there is a failure within the UPS hardware, or if the UPS is overloaded.

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Advantages:

• Continuous & total power conditioning
• Failsafe/overload protection with static bypass facility
• No break on mains failure
• Wide input voltage tolerance
• Recommended with Generator sets

Disadvantages:

• More expensive than other types of UPS technology

Offline Standby Technology

During normal operation of an Offline UPS, the power flows straight through the unit and hence only RFI filtering is usually provided. When the input voltage fails or fluctuates outside of a pre-set tolerance window, the UPS detects this and a relay will close, allowing the UPS to start feeding UPS battery power via the inverter. The inverter is then switched on and a square, step or sine wave form output is supplied. Upon the return of mains power, the output is switched back onto mains and the inverter is turned off. Typically there will be a break of between 4-10 ms during the transfer to and from the battery mode.

Advantages:

• Low cost
• Silent operation when in standby
• Efficient

Disadvantages:

• Minimal power protection - only protects against a small percentage of problems
• Poor output voltage regulation - sags and surges will be passed straight to the load
• Break transfer to battery mode
• No failsafe - UPS will drop the load if there is a high start-up current, overload or inverter failure

Line-Interactive Technology

A line-interactive UPS operates in a very similar fashion to an offline UPS, except with the advantage of better filtering and output voltage boost/reduce features. It does not eliminating mains-borne interference, line-interactive technologies does reduce the impact of spikes, surges and sags by 'clipping' the peaks and valleys, boosting power or switching to battery back up. As with offline UPS, when the input voltage fails or fluctuates outside of a pre-set tolerance window, the UPS detects this and a relay will close allowing the UPS to start feeding battery power via the inverter. The inverter, in a good line-interactive UPS, will supply a sine wave output. Upon the return of mains power, the output is switched back onto mains and the inverter is turned off.

As with offline UPS, typically there will be a break on the transfer to and from battery mode, though usually this will be shorter than with an offline UPS. Some manufacturers will try to pass their line-interactive UPS off as online models by calling them 'digital online', 'inline' or 'online interactive' - make sure you know what technology the UPS you are buying actually uses.

Advantages:

• Lower cost than online
• Gives better protection than offline
• Silent operation when in standby
• Efficient

Disadvantages:

• Fluctuations, such as spikes, can still be passed straight to the load
• Break on transfer to battery mode.
• No failsafe - UPS will drop the load if there is a high start-up current, overload or inverter failure

List of Presidents of India

            The President is the head of the Republic of India and is the first citizen of India. Article 53 of the Indian Constitution states that all the executive powers of the Union shall be exercised by him either directly or through officers subordinate to him.

In the Constitution Part V (The Union) under Chapter I (The Executive) details of qualifications, election and impeachment of the President of India is given. That is Articles from 52 to 78 in Part V of the Constitution deals with the Union Executive. The President of India is also the head of the executive, legislature and judiciary of the country. 

The President holds office for a tenure of five years from the date on which he enters upon his office. However, he can resign from his office at any time by addressing the resignation letter to the Vice-President. Further, he can also be removed from the office before completion of his term by the process of impeachment. The President can hold office beyond his term of five years until his successor assumes charge. He is also eligible for re-election to that office.

The Electoral College elects the President of India, which includes the elected members of both the Houses of Parliament, the elected members of the legislative assemblies of the states and the elected members of the legislative assemblies of the Union Territories of Delhi and Puducherry and the representation of its members is preferential. Their vote is single transferable and their second choice is counted too. Do you know that no law can be imposed in India without the President's signature?

1. Dr. Rajendra Prasad

Dr. Rajendra Prasad was the first President of India, who had worked as president for two terms. He was also the President of the Constituent Assembly and the Chief Leader of the Indian Independence Movement. He was awarded Bharat Ratna in 1962.

2. Dr. Sarvepalli Radhakrishnan

Dr. Sarvepalli Radhakrishnan was born on 5 September 1888, and this day is celebrated as Teacher's Day. He was awarded Bharat Ratna in 1954.

What is the Salary and Perks of the President of India?

3. Dr. Zakir Husain

Dr. Zakir Husain became the first Muslim President of India and died at his post. The immediate Vice President, V.V. Giri was made the acting President. After that, Chief Justice of the Supreme Court Mohammad Hidayatullah became acting President from 20 July 1969 to 24 August 1969. 
Mohammad Hidayatullah was awarded the Padma Bhushan in the field of art by the Government of India in 2002. He also brought a revolution of education in India. 

4. V. V. Giri

V.V Giri was the fourth President of India. His full name was Varahagiri Venkata Giri. He became the only person to be elected President as an independent candidate. In 1975, he was awarded with Bharat Ratna.

What is President’s Rule (356)

5. Fakhruddin Ali Ahmed

Fakhruddin Ali Ahmed was the fifth President of India. He was the second President who died in the post of the President. BD Jattha was made Acting President.

6. Neelam Sanjeeva Reddy

Neelam Sanjeeva Reddy became the sixth President of India. He was the first Chief Minister of Andhra Pradesh. He was directly elected to the post from Lok Sabha speaker and became the youngest President who occupied Rashtrapati Bhavan and contested twice for the post of president.

List of dignitaries allowed to fly National Flag on their vehicle

7. Giani Zail Singh

Prior to becoming the President, he was also the Chief Minister of Punjab and the Minister at the Centre. He also used Pocket Veto on the Indian Post Office Bill. During his presidency, many incidents took place, such as the Operation Blue Star, the assassination of Indira Gandhi and the 1984 anti-Sikh riots.

8. R. Venkataraman

R. Venkataraman was elected as the President of India from 25 July 1987 to 25 July 1992. Earlier he was Vice-President of India from 1984 to 1987. He has received many honours from different parts of the world. He is a receiver of "Tamra Patra" for his contributions to India's freedom struggle. Besides this, the Russian government had conferred the Soviet Land Prize for writing the travelogue on former Tamil Nadu Prime Minister, Kumaraswami Kamaraj's.

9. Dr. Shankar Dayal Sharma

He was the eighth Vice President of India before becoming president. From 1952 to 1956 he was the Chief Minister of Bhopal and Cabinet Minister from 1956 to 1967. The International Bar Association gave them the 'Living Legend of Law Award of Recognition' due to multi-achievements in the legal profession.

10. K R Narayanan

K. R. Narayanan was the first Dalit President of India and the first Malayali person to receive the highest office of the country. He was the first President to vote in the Lok Sabha elections and addressed the state assembly.

11. Dr. A.P.J Abdul Kalam

Dr. A. P.J. Abdul Kalam came to be known as ‘Missile Man of India’. He was the first scientist who took over the post of President and the first President of India who won the most votes. In his directorial, Rohini-1 satellites, Agni and Prithvi missiles were successfully launched. The Pokhran-II nuclear tests conducted in India in 1998 after the original nuclear test of 1974 saw him in a pivotal political, organisational and technical role. He was awarded the Bharat Ratna in 1997.

Dr. A.P.J. Abdul Kalam – The Missile Man of India

12. Shrimati Pratibha Singh Patil

She was the Governor of Rajasthan before becoming the President. From 1962 to 1985 she was a member of the Maharashtra Legislative Assembly five times and was elected from Amravati to the Lok Sabha in 1991. Not only this, she is also the first woman president to fly Sukhoi.

13. Pranab Mukherjee

Pranab Mukherjee was the finance minister in the central government before contesting the presidential election. He was awarded the best Parliamentary Award in 1997 and Padma Vibhushan, India's second-highest civilian honour in 2008. He died on 31 August, 2020 (Monday) at the age of 84. He was testes positive for corona and had been in a coma after a brain surgery earlier this month.

14. Ram Nath Kovind

Ram Nath Kovind was born on 1 October 1945 in Uttar Pradesh, India. He is an Indian lawyer and politician. He is the 14th and current President of India. He became the President on 25 July 2017 and is a member of Bhartiya Janata Party. He is the former Governor of Bihar. His approach towards political problems earned him praise across the political spectrum. As a Governor his achievements were the creation of a judicial commission to investigate corruption in universities.

So, these are the Presidents of India from 1947 to 2021.

Mouse

 Definition – Mouse is a pointing input device of computer. Mouse help to control cursor that is visible on the computer screen while moving the mouse on flat surface place. Its name was originated by its shape that look as mouse, because it has elliptical shaped with mouse tail. Mouse reduces usability of a keyboard. 

Traditional mouse was connected with computer through cable or cord, but now these days in the market have to various mouse are available such as wireless mouse, those mice do not need any physical wire to make connection with computer. In technology time, some mouse has some extra buttons for performing other special tasks.

1) WIRELESS MOUSE

Otherwise known as a cordless mouse, these refer to every mouse that does not have a piece of cable sticking out; Instead of using the “traditional” cables, wireless mice use radio frequency (RF) to communicate with computer devices. There are 2 parts to the equation:

• The mouse itself acts as the transmitter, giving out wireless signals as you move and click.
• The computer will receive those wireless signals and act accordingly.

As to the “wireless signals” part, please take note that it is not universal – Some wireless mouse uses the common Bluetooth standard, some uses a 2.4 GHz wireless standard, and a few others have their own proprietary wireless USB dongle.

The good: Freedom! Carry the mouse all around, no messy wires to deal with.

The bad: Requires batteries. Even though wireless mouse uses very little power and should last pretty long, but they still need fresh batteries once in a while… Running out of batteries in the middle of a game or presentation is always a bad situation.

 

2) WIRED MOUSE

As you might have guessed it, wired mice refer to every mouse that has an attached cable and requires to be plugged into a computer device. For those who are thinking that wired mice are “low tech”, “outdated”, and “inferior” – They are not, and are essentially the same as their wireless counterparts… Less wireless circuits and no batteries required.

The good: Will never run out of battery… Because there is none.

The bad: You will have to deal with a piece of cable.

 

3) MECHANICAL MOUSE

Source: Wikipedia

The mechanical mouse is what we use in the good old days and one of the most traditional mice in the history of computers. It is otherwise known as a ball mouse because it uses a rubber ball to detect motion – That ball spins along as you move the mouse, and sensors will pick up on which direction you moved.

The good: For collection… A mechanical mouse is kind of cool, but sadly, they have gone extinct and no longer manufactured.

The bad: Mechanically driven, the wheels and sensors will wear out over time.

 

4) OPTICAL MOUSE

This is the common Joe mouse that you see everywhere these days. But instead of using a rubber ball and mechanical sensors, an optical mouse uses an LED and detects movement by sensing changes in the reflected light.

The good: No dirty rubber balls to clean. But please take note that even though the optical mouse uses light to detect motion, it is not totally “mechanical free” – The buttons and scroll wheel are still mechanical in nature and will wear out over time… It’s just that optical mice will last longer with less mechanical parts.

The bad: Optical mice will not work properly on surfaces that do not reflect light, such as a piece of clear glass or plastic.

 

5) LASER MOUSE

The laser mouse is also a kind of optical mouse, and the working principles are the same – To sense the movement by reflecting light. But just as the name implies, a laser mouse uses a laser beam instead of an LED. This basically allows the mouse to be used on glass and plastic surfaces due to the different properties of light but suffers from some inaccuracy.

The good: Works on glass and plastic surfaces.

The bad: Not as accurate an optical mouse.

 

6) GAMING MOUSE

While a typical mouse usually only has 3 buttons, a gaming mouse is characterized by having many buttons and touting itself to be accurate. These extra buttons are often programmable to do various things… Mostly for the purpose of gaming.

The good: Programmable buttons, very useful even for non-gaming purposes. For example, they can be used as forward and backward buttons for web browsing or video playback.

The bad: Big and bulky, not for those who are looking for something more delicate.

 

7) TRACKBALL MOUSE

A trackball mouse is something like an upside-down ball mouse. Instead of moving the mouse around, it detects motion by spinning the ball using the thumb or palm of the hand. Even though it works similarly to the ball mouse, the design of the trackball mouse is totally different.

The ball itself is typically made of dense glass or plastic, it is smooth and does not attract dirt as sticky rubber does. Some trackball mouse is also made to be held in one hand and acts more like a remote control than a mouse.

The good: The gadget stays stationary on the desk or is handheld. The cord will never get tangled… Unless you intentionally want to.

The bad: Just like a ball mouse, it uses mechanical sensors that are susceptible to mechanical failures.

 

 

8) STYLUS MOUSE

This is a “mutated mouse” that is a cross in between a pen and mouse. Favored by digital artists, the stylus mouse is about the size of a very fat brush, typically used for freehand drawing with computers. Yep, some of the higher-end stylus mice are even sensitive to touch pressure for emulating actual brush strokes on paper.

The good: If you like to draw, this is your cup of tea.

The bad: Not your conventional mouse, the better stylus mice can be expensive.

 

9) PRESENTATION MOUSE

Once upon a time, we have to carry a separate laser pointer, mouse, and extra need one person to press the mouse for presentations… We often have to shout “next slide” for that someone to click on the mouse. Some smart monkeys thought it will be a good idea to combine a mouse and laser pointer together, and it is.

The good: Laser pointer and mouse, 2-in-1. Some can function as a smart TV remote as well.

The bad: Not your conventional mouse. Depending on the design, some presentation mouse doesn’t have a trackball nor ways to move the cursor.

 

10) VERTICAL MOUSE

Yes, this is a mouse that stands upright, and you sort of “grab” it… Probably one of the “weirder” mice in the entire list, but this design has so-called “better ergonomics”.

The good: Supposed to be ergonomic, and more comfortable to use for long hours.

The bad: Not symmetrical, have to buy specifically for left or right-handed.

 

Keyboard

A keyboard is one of the primary input devices used with a computer. Similar to an electric typewriter, a keyboard is composed of buttons used to create letters, numbers, and symbols, and perform additional functions. The following sections provide more in-depth information and answers to some of the frequently asked questions about the keyboard.

1. Flexible Keyboard

These keyboards work just the same as standard keyboards but are meant for people on the move. They are typically made of silicon, which is water and dust-resistant and don’t require constant cleaning.

2. Ergonomic Keyboard

The ergonomic keyboard is designed to reduce the strain of constant typing on the wrist and other problems that stem from that.

These keyboards prevent musculoskeletal problems such as Repetitive Strain Syndrome (RSI), something that can be caused by long hours of using keyboards.

Ergonomic keyboards are designed to angle the hands the way they would naturally fall and typically feature padding for the wrists to rest on.

3. Gaming Keyboard

Gaming keyboards are created for use for long periods of time, often adopting ergonomic designs for comfort and also lighted keys for playing in the night.These keyboards are also built with programmable keys that can be adapted to the kind of gamer you are. They have an extra thick coat of paint on the keys, more often used for gaming, such a W, A, S, D and the space bar.  

4. Wireless Keyboard

The wireless keyboard is exactly what it’s called; a keyboard without a wire. It is connected to your computer with infrared, 2.4 GHz WiFi or more often through Bluetooth.These keyboards can be used if you connect your computer to either a screen or television so you can control it from the comfort of your bed or sofa. They are relatively inexpensive and very easily available.

5. Multimedia/Internet Keyboard

Both multimedia and internet keyboards are just regular keyboards with a few extra options. For multimedia designers, the keyboards feature volume control and media application launch buttons.

6. Virtual Keyboard

A virtual keyboard is essentially just software that allows you to type without the need for actual physical keys. The way you to use this keyboard is with the use of a touch screen featured in newer laptop releases and tablet computers.

7. Laptop Keyboard

Laptop keyboards have what we call “chiclet style” keys, which are sleeker than traditional keys to fit in thinner design laptops.