jobscumstudy: Physics

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Monday, 30 May 2016

MSc Entrance Exam Detail in MS University

Program:

Master of Science - Physics [M.Sc. - Physics]

Details:

For M. Sc.
Eligibility for Admission

A minimum of 50% marks or equivalent grade in aggregate at B. Sc. (General or Honours) or equivalent degree from a university endorsed by the Maharaja Sayajirao University of Baroda, Vadodara. The student must have studied relevant subject at B. Sc. For subjects like Biochemistry, Microbiology, PGD Applied Biochemistry and Medical Biotechnology; students with B. Sc. Degree in any of the life science subjects or chemical science subject are eligible. For Biostatistics, students with B. Sc. in Biological, Chemical or Mathematical sciences are eligible.
Minimum Eligibility marks for students of different categories:

	General	SC/ ST	SEBC	Physically
				Handicapped
B. Sc. Marks	50%	PASS	45%	47%

Government of Gujarat rules for the reservation quota will be observed in admission for SC/ ST/ SEBC/ Physically handicapped/ Defence persons/Sports person etc.

Allocation of seats for the students from Vadodara district, other districts of Gujarat and from other states of India will be as per the University rules.

Candidates who have appeared for the final year of the qualifying examination may also apply and appear in the Entrance Test. However, the eligibility will be verified and admission will be confirmed only after production of the original mark sheet of the qualifying examination.

Students with B. Sc. (Electronics) are NOT eligible for admission to M. Sc. in Physics.

Program level:

Program nature:

Degree

Program mode:

Subjects offered:

Eligibility criteria:

As mentioned above.

Intake capacity:

55 Seats

Duration of Program:

2 years (4 Semesters)

Mode of Admission:

Entrance test

Program Fees:

See Prospectus for detail

Opening Dates for online application:

4/5/2016

Closing Dates for online application:

06/06/2016

Contact Person Info:

Prof. J P Singh, 0265-2795339, janardanmsu@yahoo.com

Prospectus: Download: https://www.dropbox.com/s/h2h19daf4hutj1s/Fac%20Sci%20PG%20Prospectus%202016%2024-05-2016.pdf?dl=0

Thursday, 5 May 2016

GRAVITATIONAL Questions Bank

1. A thief stole a box with valuable article of weight ‘W’ and jumped down a wall of height h. Before he reach the ground he experienced a load of

(a) zero

(b) W / 2

(d) 2 W

2. The acceleration due to gravity g and mean density of the earth r are related by which of the following relation? Where g is gravitational constant and R is radius of the earth

(a) r =

(b) r =

(d) r =

3. When the planet comes nearer the sun moves

(a) fast

(b) slow

(d) none of the above

4. Kepler’s second law regarding constancy of arial velocity of a planet is a consequence of the law of conservation of

(a) energy

(b) angular momentum

(d) none of these

5. The period of geostationary artificial satellite is

(a) 24 hours

(b) 6 hours

(d) 48 hours

6. A geostationary satellite is orbiting the earth at a height of 6R above the surface of the earth, R being the radius of the earth. The time period of another satellite at a height of 2.5 R from the surface of earth is

(a) 6 hr

(b) 6 hr

(d) 10 hr

7. The distance of Neptune and Saturn from the sun are nearly 10¹³ m and 10¹² m respectively. Assuming that they move in circular orbits, their periodic times would be in the ratio of

(a) 10

(b) 100

(d) 1000

8. A satellite is orbiting close to the surface of the earth, then its speed is

(a)

(b) Rg

(c)

(d)

9. If the gravitational force between two objects were proportional to 1/R (and not as 1/R²) where R is separation between them, then a particle in circular orbit under such a force would have its orbital speed v proportional to

(a)

(b) R⁰

(d)

10. Imagine a light planet revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between the planet and the star is proportional to then

(a) T² a R²

(b) T² a

(d) T² a R³

11. The period of a satellite in a circular orbit of radius R is T. The period of another satellite in circular orbit of radius 4R is

(a) T/4

(b) 8T

(d) T/8

12. A planet moves around the sun. At a point A, it is closest from the Sun at a distance d₁ and has a speed v₁. At another point B, when it is farthest from the sun at a distance d₂, its speed will be

(a)

(b)

(c)

(d)

13. The period of geostationary artificial satellite of earth is

(a) 6 hours

(b) 12 hours

(d) 365 days

14. If ‘r’ represents the radius of the orbit of a satellite of mass ‘m’ moving round a planet of mass ‘M’, the velocity of the satellite is given by

(a) v² =

(b) v² =

(d) v =

15. A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is

(a) Positive

(b) Negative

(d) may be positive or negative

16. The escape velocity of projection from the earth is approximately (R = 6400 km)

(a) 7 km/sec

(b) 112 km/sec

(d) 1.1 km/sec

17. If the earth is 1/4^th of its present distance from the sun, the duration of the year would be

(a) 1/4 of the present year

(b) 1/6 of the present year

(d) 1/16 of the present year

18. The relation between escape velocity and orbit velocity is

(a) v_e =

(b) v_e = v_orb

(d) v_e = v_orb

19. There is no atmosphere on the moon because

(a) it is closer ot the earth

(b) it revolves round the earth

(d) the escape velocity of gas molecules is less than their root mean square velocity here

20. If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth’s surface would

(a) decrease by 2%

(b) remain unchanged

(d) will increase by 9.8%

21. F_g and F_e represents gravitational and electrostatic forces respectively, between the two electrons situated at a distance of 10 m. The ratio F_g/F_e is of the order of

(a) 10⁴³

(b) 10³⁶

(d) 10^-³⁶

22. The value of ‘g’ at a particular point is 9.8 m/sec² suppose the earth suddenly shrink uniformly to half its present size without losing any mass. The value of ‘g at the same point (assuming that the distance of the point from the centre of the earth does not shrink) will become

(a) 9.8 m/sec²

(b) 4.9 m/sec²

(d) 2.45 m/sec²

23. The planet mercury is revolving in an elliptical orbit around the sun as shown in figure. The kinetic energy of mercury will be greater at

(a) A

(b) B

(d) D

24. The orbit velocity of an artificial satellite in a circular orbit just above the earth’s surface is v. For a satellite orbiting at an altitude of half of the earth’s radius, the orbital velocity is

(a)

(b)

(c)

(d)

25. If the change in the value of g at the height h above the surface of the earth is the same as at a depth x below it, then (both x and h being much smaller than the radius of the earth)

(a) x = h

(b) x = 2 h

(d) x = h²

^{Answer key}

^1.A^2.C^3.A^4.B^5.A^6.A^7.C^8.C^9.B^10.B^11.B^12.A^13.C^14.C^15.B^16.C^17.C^18.A^19.D^20.C^21.C^22.A^23.A^24.C^25.B

^{Also download in PDF:}

^{https://www.dropbox.com/s/4opem4vkucscxp3/gravitational%281%29.pdf?dl=0}

Tuesday, 3 May 2016

Guidelines for Preparing for MSc Physics Entrance Exam

General guidelines for preparing for M.Sc Physics Entrance Exam

Students preparing for M.Sc Physics Entrance Exam should obtain good text books related to the topics mentioned in the syllabus of the exam. They should prepare a better study plan for the efficient utilization of the time available to prepare for the exam. They can make use of guides and preceding year question papers for practicing. Students can also go for coaching centers to improve their skills.

M.Sc Physics Entrance Exam Pattern

M.Sc Physics Entrance Exam will consist of multiple choice questions of objective type. Candidates need to choose right answer from the given options. In some entrance exams there will be negative marking for giving wrong answers. Candidates should choose their answers carefully in those exams. Questions for this test will be asked from the subjects given below

1. Motion in one, two and three dimension

2. Work power and Energy

3. Gravitation

4. Simple Harmonic Motion

5. Elasticity surface tension

6. Calorimetry

7. Thermodynamics

8. Thermometry

9. Wave motion

10. Optics

11. Electromagnetism and magnetism 12. Electromagnetic induction

13.Semi-conducting devices

14. Radio-activityNuclear structure and nuclear energy

15. Matter waves

Set up a full proof study Plan

Candidates who want to score well in the entrance exam should prepare for the exam with a good study plan. They should set up this plan as early as possible according to the extent of difficulty in each subject. Study plan prepared by the students should specify enough time for studying different topics and taking intervals. Target for each day should be specified on the study plan. Candidates should try to follow that study plan every day.

Ladders in preparing for the Exam

As there will be many numerical problems in Physics, students should manage their time to solve each question properly. They should practice with previous question papers to reduce the time taken to solve each problem. They can attend coaching centers to improve time management

Friday, 29 April 2016

MSc Physics Syllabus And Regulations Saurashtra University

Physics. https://drive.google.com/file/d/0B7j9S6dAN2OtZ0h0ckg0VkVVTzQ/view?usp=docslist_api

Tuesday, 19 April 2016

Classification of Transducers

1. Based on the Physical phenomenon

1. Primary: The transducer which sends the measurement and converts them into another variables[ displacement, strain, etc.] and whose output forms the input of transducer is called as Primary transducer.

1. Bourdon Tube: Used in Pressure measurements.

2. Strain Gauge: Used in force and Strain measuremants.

2. Secondary: The transducer which converts the output of first transducer into an electric output called Secondary transducer.

1. LVDT: Used to measure displacement, Force, Pressure and position.

2. Based on the power type

1. Active: Which do not recuire any power sources for their operation. They work on energy conversion principle. They produce an electrical signal proportional to the input[ Physical quantity ].

1. Thermocouple: Used to maesure Temperature, Radiation and Heat flow.

2. Photovoltaic Cell: Used in light meter and solar cell.

2. Passive: Which recuire an external power source for their operation. They produce an output signal in the form of some variation in resistance, capacitance or any other electric parameter. Which than has to be converted to an equivalent current or voltage signal.

1. Photocell [ LDR ]

2. Capacitive transducers: Used to measure liquid level.

3. Resistive transducers: Used to measure Temperature, Pressure, Displacement.

4. Inductive transducer: Used to measure Pressure, Vibration, Position, Displacement etc.

3. Based on the the type of output

1. Analog: The transducer which produces their outputs in analog form. A form which continuous function of time.

1. Strain gauge: Used to mearsure Displacement, Force and Torque.

2. Thermistor: Used to mearsure Temperature and Flow.

2. Digital: The transducer which producess their output in digital form. A form of pulses.

1. Turbine meter: Used to mearsure Flow.

4. Based on the electrical phenomenon

1. Resistive: Change in resistance of these sensors when certain physical quantity is applied to it.

1. Resistance thermometer: Used to measure Temperature and Radiant Heat.

2. Potentiometer device: Converts the change in displacement into change in the resistance. Used to mearsure Displacement and Pressure.

3. Thermistor: Used to mearsure Temperature and Flow.

2. Capacitive: The change in distance between the two plates produced by the displacement results in change in capacitance.

1.Dielectric gauge: Used to measure Thickness and Liquid Level.

2. Capacitor microphone: Used to measure Noice, Speech and Music

3. Indutive:

1. Reluctance Pick-up: Used to mearsure Pressure, Vibration, Position, Displacement.

2. Eddy current gsuge: Used to mersure Sound, Force, Pressure.

3. LVDT: Used to measure displacement, Force, Pressure and Position.

4. Photoelectric: Converts light beam into a usable electric signal. Used to mearsure light intensity.

5. Photovoltic: Used to Photovoltaic cell and Photographic work.

5. Based on the non-electrical phenomenon

1. Linear displacement

2. Rotary displacement

6. Based on transduction

1. Transducer: A mearsuring device which measures and converts non-electrical variable into electrical variable.

1. Thermocouple: Used to maesure Temperature, Radiation and Heat flow.

2. Inverse transducer: A measuring device which measures and converts an electrical variable into non-electrical variable.

1. Piezo-electric crystal: Used to measure Pressure, Vibration and Acceleration.

Photoconductive Transducers:

Used to maesure Radiation at all Wavelengths.

Ionization Transducer:

Converts displacement to a voltage through capacitance change. Used to measure stedy magnetic field.

Hall-Effect Transducers

Digital Displacement Transducers:

Used to measure angular and linear displacements.

Mechanical Transducer

Transducsrs depending upon the change in property or the energy they bring about to measure specified physical quantities.

The mechanical transducsers are the mechanical elements that are used for converting one form that can be easily measured.
There are number of mechanical transducers, some of the commonly used

application of CRO

Linear Variable Differential Transformer

1. Linear Variable Differential Transformer

It is a Passive Transducer.

1. Principle

LVDT works under the principle of mutual induction and the displacement which is a non-electrical energy is converted into an electrical energy.

2. Contraction

1. Primary Coil

2. Secondary Coil 1 S1

3. Secondary Coil 2 S2

4. Ferromagnetic Core

5. Shaft

6. Shield

1. The ferromagnetic core is the moving component whose position within the shaft is sensed.

2.            It is surrounded by one primary winding in the center of the former.

3.            The two secondary windings are equal and opposite direction.

4.            If the left secondary windings in the clockwise direction, the right secondary windings will be in the anticlockwise direction.

5.            The net output voltages will be the difference in the voltages between the two secondary coils.

6.            A cylindrical shield protects the windings from damage.

7.            The two secondary coils are represented as S1 and S2.

8.            The induced voltages V1 and V2 in the two secondary are equal but anti phase.

1.    Working

The working of LVDT by splitting the cases into 3 based on the iron core position insulated former.

1.      Center or Null Position

2.      Right of Null Position

3.      Left of Null Position

CASE-1

® On applying an External force which is the Displacement.

® If the core reminds in the null position it without providing any movement.

® Then the voltages induced in both the secondary coils are equal.

® The core is in the centre V1 and V2 are equal and Opposite.

® Hence they cancel out and the Output voltage V₀ is zero.

                 V₀ = V1 – V2 = 0

CASE-2

® When an external force is applied and it the steel iron core tends to moves towards coil S2.

® V2 is increased but V1 is decreased in magnitude will each other.

® Therefore the net output voltage

V₀ = V2 – V1

® This is in phase with V2.

CASE-3

® When an external force is applied and it the steel iron core tends to moves towards coil S1.

® V1 is increased but V2 is decreased in magnitude will each other.

® Therefore the net output voltage

               V₀ = V1 – V2

® This is in phase with V1.

v The magnitude of V₀ is a function of the distance moved by the one core.

v Phase indicates as to in which direction it has moved.

If core is attached to a moving object, the magnitude of V₀ gives the position of that object.
4. Advantages

Ø High output.

Ø High sensitivity (50mV to 300mV).

Ø Very good linearity.

Ø Produces high resolution (>10mm).

Ø Low power consumption.

Ø Low hysteresis.

Ø Small in size and weight less.

Ø It is rugged in design and can also be assigned easily.

Ø Maintains a liner relationship between the voltage difference output and displacement from each position of the core for a displacement of about 4mm.

Disadvantages

Ø Very high displacement is required for generating high voltage.

Ø Shielded is required since it is sensitive external magnetic field.

Ø The Performance of the transducer gets affected by vibrations.

Ø Produces output with less power.

Ø The efficiency of the device affected by temperature.

Ø A demodulator will be needed to obtain a d.c. output

Applications

Ø Acting as a secondary transducer.

Ø LVDT can be used to measure force, weight and pressure.

Ø Measurement of roll position.

Ø Used as an absolute position sensor even if power is switched off.

Ø Used to measure displacement ranging from fraction mm to cm.

Ø Measurement of material thickness in hot strip or slab steel mills.

Saturday, 16 April 2016

Transducer

1. It may be defined as any device that converts energy is one form to energy in other form.
2. A transducer is an electronic device that converts energy from one form to another form. 3. A transducer converts a signal in one form of energy to a signal in another form.
Most of the transducers either convert electrical energy into mechanical displacement and/or convert some non-electrical physical quantity to an electrical signal.
In an electronic instrumentation system, the functions of a transducer are two fold
1. To detect or sense the presence, magnitude and changes in the physical quantity being measured.
2. To provideta proportional electrical output signal as shown in fig.