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Questions Related to physics

A steel wire of mass $4.0\ g$ and length $80\ cm$ is fixed at the two ends. The tension in the wire is $50\ N$. The wavelength of the fourth harmonic of the fundamental will be

physics oscillations and waves standing waves in strings standing waves reflection of waves

  1. $80\ cm$

  2. $60\ cm$

  3. $40\ cm$

  4. $20\ cm$

Show answer
Correct Option: C
Explanation:

$m=$ mass per unit length

$=\cfrac { 4\times { 10 }^{ -3 } }{ 80\times { 10 }^{ -2 } } =0.005\quad Kg/m$

given $T=50 N$

$L=80 cm=0.8m$

$\therefore v=\sqrt { \cfrac { T }{ m }  } =\sqrt { \cfrac { 50 }{ 0.005 }  } =100m/sec$


Fundamental frequency 

${ f } _{ 0 }=\cfrac { 1 }{ 2L } \sqrt { \cfrac { T }{ m }  } \\ =\cfrac { 1 }{ 2\times 0.8 } \sqrt { \cfrac { 50 }{ 0.005 }  } \\ =625\quad Hz$


$\therefore { f } _{ 4 }$ Frequency of fourth harmonic 

$4{ f } _{ 0 }=4\times 62.5=250\quad Hz$

As we know

${ v } _{ 4 }={ f } _{ 4 }{ \lambda  } _{ 4 }\\ \therefore { \lambda  } _{ 4 }=\cfrac { { v } _{ 4 } }{ { f } _{ 4 } } =\cfrac { 100 }{ 250 } \\ =0.4m\quad \\ =40 cm$

The wave-function for a certain standing wave on a string fixed at both ends is $y\left( x,t \right) =0.5\sin { \left( 0.025\pi x \right)  } \cos { 500\ t } $ where $x$ and $y$ are in centimeters and t is in seconds. The shortest possible length of the string is: 

physics oscillations and waves standing waves in strings standing waves reflection of waves

  1. $126\ cm$

  2. $160\ cm$

  3. $40\ cm$

  4. $80\ cm$

Show answer
Correct Option: C
Explanation:

For the shortest possible length, it should be allowing fundamental frequency resonance.

In fundamental frequency
$L=\dfrac { \lambda  }{ 2 } \quad \quad \quad \quad \left( \because K=\dfrac { 2\pi  }{ \lambda  }  \right) $
$=\dfrac { 2\pi /K }{ 2 } =\dfrac { \pi  }{ K } $
from $y=0.5\sin\left( 0.025\pi x \right) \cos\left( 500t \right) $
$K=0.025\pi \quad \quad \quad (on\quad comparing\quad with\quad y=A\sin\left( Kx \right) \cos\left( wt \right) )$
$\therefore \quad L=\dfrac { \pi  }{ 0.025\pi  } =\dfrac { 1000 }{ 25 } $
$\left[ L=40cm \right] $

Hence Option (C) is correct.

The second overtone of an open pipe has the same frequency as the first overtone of a closed pipe 2 m long. The length of the open pipe is

physics oscillations and waves standing waves in strings standing waves reflection of waves

  1. 8 m

  2. 4 m

  3. 2 m

  4. 1 m

Show answer
Correct Option: B
Explanation:

$l _0=$ length of organ pipe (open)

$l _c=$ length of close organ pipe
frequency of open pipe$=\cfrac{3V}{2l _0}$
frequency of close pipe $=\cfrac{3V}{2l _c}$
$\therefore \cfrac{3V}{2l _0}=\cfrac{3V}{4l _c}\2l _0=4l _c\2\times2m=4m$
B is the correct option.

A guitar string is $90 cm$ long and has a fundamental frequency of $124 Hz$. To produce a fundamental frequency of $186 Hz$, the guitar should be pressed at ?

physics oscillations and waves standing waves in strings standing waves reflection of waves

  1. $60 cm$

  2. $30 cm$

  3. $20 cm$

  4. $ 10 cm$

Show answer
Correct Option: A
Explanation:

Here, $L _1 = 90 cm, \upsilon _1 = 124 Hz, \upsilon _2 = 186 Hz, L _2=?$

According to the law of length, $\upsilon _2L _2 = \upsilon _1L _1$

$\therefore \upsilon _2= \dfrac{\upsilon _1L _1}{\upsilon _2} = \dfrac{124 \times 90}{186} = 60 cm$

Which most popular input device used today for interactive processing & for the on line entry of data for batch processing.

classification of computer introduction to the information age physics

  1. Mouse

  2. Magnetic disk

  3. Visual display terminal

  4. Card punch

  5. None of the above

Show answer
Correct Option: C
Explanation:

Visual display terminal most popular input device used today for interactive processing & for the on line entry of data for batch processing.

A video display unit (VDU) consists of: A computer output device that uses a cathode ray tube or other technology to present visual images. One or more input devices, such as a keyboard , a mouse , or both. A synonym sometimes used in the United States is video display terminal ( VDT ).

A video display unit (VDU) consists of: A computer output device that uses a cathode ray tube or other technology to present visual images. One or more input devices, such as a keyboard , a mouse , or both.

Computer follows a simple principle called GIGO which means _________________.

classification of computer introduction to the information age physics

  1. Garbage in garbage out

  2. Garbage input good output

  3. Good input good output

  4. Greater instructions greater output

Show answer
Correct Option: A
Explanation:

GIGO means garbage in garbage out which means if you provide garbage as input the result /output will be garbage only . so if you input incorrect data the output would be not informative and would we incorrect

An IBM System$/38$ represents the computer class of.

classification of computer introduction to the information age physics

  1. Small-scale computer

  2. Medium-scale computer

  3. Large-scale computer

  4. Super computer

  5. None of the above

Show answer
Correct Option: A
Explanation:

An IBM System/38 represents the computer class of small-scale computer.

The System/38 was a midrange computer server platform manufactured and sold by the IBM Corporation. The system offered a number of innovative features, and was the brainchild of Frank Soltis and Glenn Henry. IBM announced the System/38 in 1978.

The System/38 was a midrange computer server platform manufactured and sold by the IBM Corporation. The system offered a number of innovative features, and was the brainchild of Frank Soltis and Glenn Henry. IBM announced the System/38 in 1978.[1] Developed under the code-name "Pacific", it was made commercially available in August 1979. The System/38 was oriented toward a multi-user system environment.

What is the name of the 64-bit Microprocessor developed by AMD?

classification of computer introduction to the information age physics

  1. Opteron

  2. Risc-9000

  3. iMac

  4. Athlon

Show answer
Correct Option: A
Explanation:

Opteron is the name of the 64-bit Microprocessor developed by AMD.

Opteron is family of 64-bit x86 server uniprocessors and multiprocessors designed by AMD as a successor to the Athlon MP family. Opteron processors are designed for workstations and servers and are a direct competition to Intel's Xeon processors.

Opteron is the name of a family of CPUs within the AMD64 line. Designed by AMD for the server market, it competes with Intel's Xeon. For Socket 940 and Socket 939 Opterons, each chip has a three-digit model number, in the form Opteron XYY.

Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64). It was released on April 22, 2003, with the SledgeHammer core (K8) and was intended to compete in the server and workstation markets, particularly in the same segment as the Intel Xeon processor. Processors based on the AMD K10 microarchitecture (codenamed Barcelona) were announced on September 10, 2007, featuring a new quad-core configuration.

AMD's main products include microprocessors, motherboard chipsets, embedded processors and graphics processors for servers, workstations and personal computers, and embedded systems applications. AMD is the second-largest supplier and only significant rival to Intel in the market for x86-based microprocessors.

Which is not necessary when using bar codes in supermarkets?

classification of computer introduction to the information age physics

  1. Point-of sale(POS) terminal

  2. Check digit on the bar code

  3. Price on the shelf

  4. Price on the goods

  5. None of the above

Show answer
Correct Option: C
Explanation:

Price on the shelf is not necessary when using bar codes in supermarkets.

It also contains a check digit, so that the computer can validate that the data has been read in correctly. The barcode does not contain price. The price is held in the database instead. This makes it easy to change if there are special offers or prices go up.

The Universal Product Code (UPC) is a barcode symbol that is widely used in the United States, Canada, United Kingdom, Australia, New Zealand, in Europe and other countries for tracking trade items in stores.

A computer will function only if it.

classification of computer introduction to the information age physics

  1. Has a control unit

  2. Is given input data

  3. Has a program in its memory

  4. Has software package

  5. None of the above

Show answer
Correct Option: C
Explanation:

A computer will function only if  has a program in its memory.

The chips that make up a computer's internal memory come in two broad flavors known as RAM (random access memory) and ROM (read-only memory). RAM chips remember things only while a computer is powered on, so they're used for storing whatever a computer is working on in the very short term.

Organizing Data Storage. Data is stored as lots of binary numbers, by magnetism, electronics or optics. ... The computer's BIOS contains simple instructions, stored as data in electronic memory, to move data in and out of different storage locations and around the computer for processing.