1. Assertion (A) : The skill of estimation is important for all of us in our daily life. Reason (R) : The skill of estimation reduces our consumption of time.
2. What is the measuring unit of the thickness of a plastic carry bag?
3. The mass of 40 apples in a box is 5 kg. (i) Find the mass of a dozen of them.
4. With the help of vernier caliper we can have an accuracy of 0.1 mm and with screw gauge we can have an accuracy of 0.01 mm.
5. Assertion (A) : The scientifically correct expression is “The mass of the bag is 10 kg” Reason (R) : In everyday life, we use the term weight instead of mass.
6. Assertion (A) : Distance between two celestial bodies is measured in terms of light year. Reason (R) : The distance travelled by the light in one year is one light year.
7. An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 m and 20 s?
8. A particle is moving in a circular pattern of radius r. The displacement after half a circle would be.......
9. In which of the following cases of motions, the distance moved and the magnitude of displacement are equal?
10. A body is projected up with an initial velocity u m/s. It goes up to a height, ‘h’ metres in seconds time. Then it comes back at the point of projection. Considering negligible air resistance, which of the following statement is true?
11. Which of the following is correct about uniform circular motion (i) direction of motion is continuously changed (ii) direction of motion is not changed (iii) speed and direction both remain constant (iv) speed is constant but direction is changing
12. An ant moves from one corner of a room diagonally to the opposite corner. If the dimensions of the hall are 8m x 6m, the displacement of the ant is
13. Scuba divers wear special suits to withstand.............
14. To find out relative density of the substance, with respect to density of water……………C is taken.
15. A solid floats in liquid with a portion of it being submerged. Then (a) The liquid exerts an upthrust equal to weight of the solid (b) The weight of the dispersed liquid is equal to the weight of solid (c) Solid exerts a force equal to its weight on liquid. Choose correct statements:
16. Saccharometer is used to measure the density of …………….in a liquid.
17. The reading of a spring balance when a block is suspended from it in air is 60 newton. This reading is changed to 40 newtons when the block ¡s submerged in water. Calculate the specific gravity of block.
18. Assertion (A) : The buoyant force on submerged rigid object can be considered to be acting at the centre of mass of object. Reason (R) : In rigid body, force distributed uniformly through its volume can be considered to be acting at the centre of mass of the body.
19. A current of 2A passing through the conductor produces 80 J of heat in 10 seconds. The resistance of the conductor is ……………..
20. The force between two parallel wires carrying currents has been used to define…………..
21. Two conductors of resistance 2 R and R are connected in series in a battery circuit. The ratio of heat developed In them is ……………………
22. The resistance of a conductor is R. If Its length is doubled, then its new resistance will be ……………….
23. The following is not a safety device. (a) Fuse (b) Trip switch (c) Ground connection (d) Wire
24. In India the frequency of alternating current is,
25. The direction of the magnetic field around a straight conductor carrying current can be determined by …………………
26. Which of the following instruments works by electromagnet-ic induction?
27. The most suitable material for making permanent magnets is ………………..
28. A magnetic needle is kept in a non-uniform magnetic field. It experiences …………….
29. Magnetic field lines determine ______
30. For making a strong electromagnet the material of the core should be_______.
31. A ray of light is incident towards a plane mirror at an angle of 30° with the mirror surface. What will be the angle of reflection?
32. A 10 mm long bin is placed vertically in front of a concave mirror. A 5 mm long image of the bin is formed at 30 cm in front of the mirror. The focal length of this mirror is
33. A ray of light as it travels from medium A to medium B refractive index of the medium B relative to medium A is (μB/ μA)
34. Under which of the following conditions a concave mirror can form an image larger than the actual object?
35. In torches, searchlights and head lights of vehicles the bulb is placed …………………………… of the concave mirror.
36. A boy is standing at a distance of 3m in front of a plane mirror. The distance between the boy and his image is ………………….. m
37. When we heat one end of an iron rod, its other end also gets heated. Can you say, Which one of the following is behind this?
38. On a cold day, it is hard to open the lid of a tight container. But when you gently heat the neck you can easily open the lid. why?
39. Copper and Iron are good conductors of heat. Which one of the following is not a good conductor of heat?
40. The specific heat capacity of water is
41. Two cylinders of equal height and radius are made of copper and aluminum. Which of them conducts heat faster?
42. When heat energy is added to a substance, the kinetic energy of its particles and so the particles ……………………… move at a higher speed.
43. A musical instrument is producing continuous note. This note cannot be heard by a person having a normal hearing range. This note must then be passing through...........
44. In longitudinal waves, the particle vibrates in a ………………….. direction of propagation.
45. To hear an echo, the minimum distance of the obstacle from the source of sound must be ………………
46. The speeds of sound in four different media are given below. Which of the following is the most likely speed in ms-1 with which the two underwater whales in a sea can talk to each other when separated by a large distance?
47. Who proposed the heliocentric model of the universe?
48. The period of revolution of planet A around the Sun is 8 times that of planet B. How many times is the distance of planet A as great as that of planet B?
49. The Geocentric model of universe was proposed by ……………
50. Which among the following statements is correct? (i) Meteors are attracted by the gravitational at force of earth. (ii) Meteors are travelling in low speeds. (iii) Most of Meteors are burnt by the heat generated by friction in atmosphere.