CBSE ADDA

     Measurement and Motion   :Quest Time 1. Name one object that shows multiple motions? Ans: The Earth - Rotatory and translator motion Drilling - Rotatory and downward translator motion A ball moving along the ground- Rotatory and Rectilinear motion      2. How will you measure length in SI system? Ans: Using meter scale 3. What is the quantity that can be measured? Ans: Physical quantity like mass, length and Time 4. What type of motion body moves as a whole? Ans: Translatory motion 5.Which kind of motion produce sound? Ans: Vibratory motion 6. What types of motion is noticed in the pendulum of clock and swing? Ans: Oscillatory motion and periodic 7.  Falling of apple from tree is what types of motion? Ans: Rectilinear motion. 8. Discovery of what made transport easy? Ans: Wheel 9. Motion in which the distance from the axis remain same? Ans: Circular motion 10. To and fro motion of a body about a fix point is example of

1. Out of convex mirror and concave mirror, whose focus is situated behind the mirror ? Ans: The focus of convex mirror is situated behind it. 2. For what position of an object, a concave mirror forms an enlarged virtual image? Ans: Object between pole (P) and focus (F) of the concave mirror. 3. If the focal length of a concave mirror is 25cm. What is its radius of curvature? Ans: Focal length = Radius of curvature / 2 25 = R / 2 R = 25 X 2 = 50cm. 4. A ray of light falls on a mirror normally. What are the values of angle of incidence and the angle of  reflection? Ans: Both angle of incidence and the angle of reflection are zero. 5. What is the focal length of a plane mirror? Ans: Infinite. 6. Which spherical mirror is called a divergent mirror? Ans: A convex mirror is called a divergent mirror. 7. What is the angle of incidence, when a ray of light falls on the spherical mirror from its centre of curvature? Ans: The angle of incidence is zero, when a ra

   CBSE Class 9 - Science - Chapter 10: FLOTATION   Thrust and Pressure, Pressure in Fluids, Buoyancy Fluid: Fluid is a substance that flows.  For example, liquids and gases. They take the shape of container in which they are stored. The study of fluids at rest is known as hydrostatic or fluid static’s.   The study of fluids in motion is termed as hydrodynamics. THRUST:   The normal force acting on a unit surface area of the fluid is called thrust Density: The mass per unit volume of a substance is called density. D = mass /volume  Þ Mass of substance = d x v ------------------------ (i)  SI unit is  kg/m 3 The density of water (1 g cm −3 ) PRESSURE IN A FLUID The pressure (P) is defined at the magnitude of the normal force acting on a unit surface area of the fluid. P = F/A .  Hence pressure is in directly proportional to Area of contact. For example a nail or a knife have pointed and sharp edge to reduce area of contact to ap

Class IX 1st.  Term Science Syllabus April : Unit : Matter in our surroundings Unit : Matter –Is matter around us pure Unit:  Improvement in Food Resources May: Unit : The fundamental unit of life Unit : Tissues July: Unit : Motion Unit : Force and laws of motion August: Unit : Gravitation September : Revision of the I term Syllabus and I term examinations PRACTICALS Class IX 1st.  Term Science Practical are to be conducted alongside the concepts taught in theory classes. List of Experiments 1. To test (a) the presence of starch in the given food sample (b) the presence of the adulterant metanil yellow in dal. 2. To prepare a) a true solution of common salt, sugar and alum b) a suspension of soil, chalk powder and fine sand in water c) a colloidal of starch in water and egg albumin in water