CBSE ADDA

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

Multiple Choice Questions : Physics Class X MAGNETIC EFFECTS OF ELECTRIC CURRENT 1.A magnetic field can exert force on (a)a moving magnet (b) stationary magnet  (c) moving charge (d)all of these 2.Magnetic lines of force (a)have more directions                 (b)have no physical reality (c)can be used to indicate the direction of the magnetic field of a point (d)all the above 3. When is the back emf of an electric motor the greatest? (a)when the motor is witched on (b)when the motor is speeding up (c)when the motor is at maximum speed (d)when the motor is slowing down 4.According to international convention of color coding in a wire (a)live is red, neutral is black and earth is green (b) live is brown, neutral is blue and earth is green (c) live is brown, neutral is green and earth is black (d)live is red, neutral is yellow and earth is blue 5.An electric cur

Study Materials (Class X): Term I STUDY MATERIAL FOR CLASS X TERM-I SCIENCE Download STUDY MATERIAL FOR CLASS X TERM-I SCIENCE Download STUDY MATERIAL FOR CLASS X TERM-I HINDI (COURSE-A) Download STUDY MATERIAL FOR CLASS X TERM-I ENGLISH COMM Download Courtesy: KVS ZIET Chandigarh

                                CBSE TEST PAPER -2012-13  Time: 1hr.  CHAPTER: MAGNETIC EFFECT OF CURRENT        FM: 30 1. A positively charged particle (alpha-particle) projected towards west is deflected towards north by magnetic field. The direction of magnetic field is           (a) towards south (b) towards east (c) downward (d) upward. 2. A rectangular coil of copper wires is rotated in a magnetic field. The direction of the induced current changes once in each    (a) two revolutions (b) one revolution (c) half revolution (d) one-fourth revolution. 3. Permanent magnets are made up of (a) Alnico     (b) soft iron  (c) copper (d) aluminum.                             4. Which of the following properties of a proton can change when it moves freely in a magnetic field (a) Mass              (b) speed              (c) velocity           (d) momentum 5. The direction of the magnetic field at a poin

CBSE PHYSICS: Class X Chapter 14 – Sources of Energy Science Notes.   Read full Post 10th std: Sources of energy videos Just click following links click go... A.   Hydroelectricity B.   Tidal energy C.     windmills D.   wave energy E.    Thermal electricity F.    ocean thermal energy G.   Biogas H.   Geothermal energy I.     Nuclear reactor J.    Renewable and non renewable resources K.   Solar cells L.    Nuclear fusion and nuclear fission M.   Types of nuclear reactions N.   Tidal energy You might also like: Class X Chapter 14 – Sources of Energy Science Notes and MCQ Chapter Source of Energy class 10 th  CBSE FORMATIVE ASSESSMENT Paper-1 Extra score questions for Ch: Sources of energy 10th source of energy solved important questions Solved GIST OF THE LESSON CBSE PHYSICS:

            (Practice) MCQ of Electricity 1.Electricity constituted by electric charges at rest on the surface of a conductor is called a. Electricity b. Potential difference c. Current electricity d. Static electricity  2.The closed path between two points at different potentials, to make the electric current flow is called a. Electric circuit b. Electric current   c. Electric potential d. Electric cell. 3. Direction of conventional current is taken from a. Negative to positive b. Positive to negative c. It could be from positive to negative or negative to positive d. None of these. 4. With increase in temperature, resistance of a conductor  a. Decreases                                                      b. Increases       c . May decreases or increases depending on temperature   d. It does not depend on temperature. 5. In series combination, resistance increases due to increase in