Sciece and Technology Point

  The Center of Gravity of a baby, while crawling, remains quite low and also the line of actions of its body weight always passes through the base. As the baby tries to stand, the Center of gravity of the body goes up and the body become unstable. To keep the body stable the baby should keep its body erect, So that the line of action of its body weight passes through the base. While walking, placing of foot and body position of the body should be such that the Center of Gravity always passes through the base. Hence, lack of sufficient practice, babies fall down frequently.  Why does Turbulent Sea calm down if Oil is poured on the water?   Solved Questions on Rectilinear Motion  

 The surface tension of pure water is more than that of oily water. When oil is poured over sea water, naturally the oil spreads in the direction of the motion of the waves leaving uncovered sea water at the rear. Hence, surface tension of the water ahead of waves is lower than that of the water behind the waves. The water at the rear pulls the water at the front and As a result, high waves become lower.  Function of  BASS, TREBLE, VOLUME  option in an AUDIO SYSTEM QUESTIONS AND ANSWERS ON PHYSICS (HIGH SCHOOL LEVEL)  

Q.   An object, starting with an initial speed and moving at constant acceleration travels 150m in 5 s. The acceleration stops after this and in the next 5s the object travels 200m farther. Find the initial velocity and acceleration of the object. Ans : Let, the initial velocity be u m/s and acceleration of the object was a m/s 2 . In the second phase, there are no acceleration. So, the object move with constant velocity. Therefore, the velocity of the second phase =200/5 m/s =40m/s So, we can say that velocity of the object after first 5s was 40 m/s. Now, for the first 5s Initial velocity = u m/s Final velocity(v)= 40m/s Time duration(t)= 5s Acceleration= a m/s 2 Distance traveled(s)= 150m Multiplying equation (i) by 10 we get, 400=10u+50a      ...........(iii) Subtracting equation (ii) from equation (iii), Substituting, the value of a in equation (i) we get,   40=u+5⨰4 Or, u=40-20 Or, u=20 Therefore, the initial velocity of the object was 20m/s ...

  In this post we list and solve the West Bengal Public Service Commission's previous  year Physics question . In this post we arrange the question topic wise. This post is the Part-4 of this series. View Part-1 View Part-2   View Part-3   Actually, this Physics series is the part of WBPSC Previous Year SCIENCE series . Electricity Q. For measuring flow of current, the device is used        [WBPSC Miscellaneous Exam- 2012(1st)] Voltmeter Galvanometer Ammeter Potentiometer Show Answer C. Ammeter Explanation:    Ammeter is used to measure current flow in the circuit.   Voltmeter is used to measure potential difference. Galvanometer is used to detect the current flow in a circuit. Potentiometer is used to measure potential difference, emf of a cell etc. Q. What is the unit of power?        [WBPSC Miscellaneous Exam- 2012(1st)] Half life Watt Volt Jule Show Answer ...

  In this post we list and solve the previous year Physics questions of West Bengal Public Service Commission (PSC WB). It is the Part-3 of this series. view Part-1 View Part-2   View Part-4   We arrange the questions topic wise.   Actually this Physics series is the part of  WBPSC Previous Year SCIENCE series . Atomic Nucleus   Q. Which of the following is most harmful for human being ?      [WBPSC Miscellaneous Exam- 2012 (1st)]   ɑ - Particle β - Particle γ - rays Light rays Show Answer C. γ -  rays Explanation: Gamma (γ) rays are generally considered the most dangerous type of radiation to living matter. It has large penetrating power compare to alpha (ɑ) and (β) particle. Q. Which of the following radiations have the maximum penetrating power?      [WBPSC Miscellaneous Exam- 2012 (2nd)]   ɑ -rays β -rays γ - rays Light rays Show Answer C. γ -  rays Explanation: If we a...

In this post we solve the previous year Physics questions of the West Bengal Public Service Commission (WBPSC). The questions are arranged topic wise. This is the part- 2 of this series.   See the part- 1 See the part-3 See the part-4   In fact, this Physics series is the part of WBPSC Previous Year Science Questions with Solution series. Light :  Q. Light waves are         [WBPSC Miscellaneous Exam- 2012 (2nd)] Mechanical waves Longitudinal waves Electromagnetic waves None of the above Show Answer C.Electromagnetic waves Explanation:  Mechanical wave can not transmit energy through vacuum. E.g. Sound wave, water waves etc. Longitudinal wave is a wave in which the particles of the medium move parallel to the propagation of the wave. E.g. sound waves. Electromagnetic wave is created by both electric field and magnetic field. It can propagate through vacuum. E.g. light waves, radio waves. Q. Scientist C.V. Raman ...

WBPSC (West Bengal Public Service Commission) previous year questions and answers on Physics . In this series we have arranged the WB PSC previous year questions related to Physics on the topic wise. This post is Part 1 .   View Part-2 .    View Part-3 View Part-4   Actually, It is the part of WBPSC Previous Year Science Questions with Solution series .   Unit : Q. What is the unit of Power?           [WBPSC Miscellaneous Exam-2012 (1st)] Half life Watt Volt Jule Show Answer B. Watt Explanation: Unit of Potential difference is volt. Unit of Energy is Jule. Q. What is the unit of volume in CGS system ?      [WBPSC Miscellaneous Exam-2012 (1st)] Cm 2 Cm 3 Km m Show Answer B.Cm 3 Explanation: Unit of length in CGS system is Cm. So, unit of volume is  Cm×Cm×Cm=Cm 3 C=Centimetre (unit of length); G=Gram (unit of mass); S=Second (unit of time). Q. Unit of wave length is   ...