Posts

Universe

Image
  Q Draw the diagram of Ursa Major and Orion? Q Give two points of difference between galaxy and constellations? Galaxy Galaxy is a vast collection of billions of stars. There are so many galaxies in this universe. Constellations Constellation is a collection of few number of stars in a definite pattern. Only 88 constellations are known so far. Q Define 1 light year? How many meters make 1 light year? And how many light-years make one parsec? The distance traveled by the light in one year is called as one light year. One light year equals 9.46 into 10 to the power of 15 meters. 1 parsec equals 3.26 light years. Q Explain the following steps in the lifecycle of a star? Formation of a protostar? Formation of a star from protostar? Formation of a giant star from a star? Formation of a protostar. The formation of a protostar begins from a huge gaseous cloud mainly of hydrogen and some helium, and at a very low temperature of -1, 73°C.  Due to gravitational force the cloud starts contractin
Post a Comment
Read more

Sun and Nuclear Energy

  Q The mass number of isotope of an element is 239. If its nucleus has 145 neutrons, what is its atomic number? Mass no = no of protons + neutrons no of protons = 239-145 =94 No of protons = atomic no = 94 Q The number of protons in the nucleus of an element of mass number 239 is 90 what will be the number of neutrons in its isotope of mass no 243? First isotope contains 90 protons, the second isotope will also contain 90 protons. Number of neutrons is equal to mass number - number of protons 243-90 =153 Q The atomic number of an element having mass number 230 is 90. What will be the number of protons and neutrons in its nuclei? Atomic number is equal to number protons equal to 90. Number of neutrons is equals to mass number - number of protons. 230 - 90 = 140 Q The mass number of an element is 18. If it contains seven electrons, what will be the number of protons and neutrons in it? What is the atomic number of the element? Number of electrons is equal to number of protons is equal t
Post a Comment
Read more

External Combustion Engine

Image
Q Describe the working of four strokes of petrol engine? The working of a patrol engine is divided into four stages. Intake stroke In this stroke, the intake valve is open and exhaust valve is closed. The mixture of patrol vapor and air enters the cylinder through the intake valve by the downward movement of the piston. Compressions stroke. In this stroke, both of the valves are closed. The patrol air mixture is compressed to 1/8 of its original volume by the upward movement of the piston. Power stroke Spark plug will produce a little spark. The patrol, air mixture, burns rapidly with a little explosion producing a large volume of gases and a lot of heat. The heat that’s produced expands the gases rapidly. The rapid expanding gases exerts pressure on the piston due to which the piston moves outward. The moving piston pushes the piston rod and rotates the wheel through crank shaft. Exhaust stroke In the stroke the intake valve is closed and exhaust valve opens. Due to the momentum gaine
Post a Comment
Read more