MAK LABS

 4. Current Electricity and Magnetism   Exercise  Q. 1 Fill in the blanks with proper words. (magnetism, 4.5V, 3.0V, gravitational attraction, potential difference, potential, higher, lower, 0V) (a) Water in the waterfall flows from a higher level to the lower level because of gravitational attraction . (b) In an electric circuit, electrons flow from a point of lower potential to the point of higher potential. (c) The difference between the electrostatic potential of the positive end and the negative end of an electric cell is the potential difference of the cell. (d) Three electric cells of potential difference 1.5 V each have been connected as a battery. The potential difference of the battery will be 4.5V . (e) An electric current flowing in a wire creates magnetism around the wire. Q. 2 Show how to join 3 dry cells to form a battery (diagram). Ans. To form a battery (series connection), connect the positive...

 3. Force and Pressure   Exercise  Q. 1 Write proper word in the blank space. (a) The SI unit of force is Newton . (Dyne, Newton, Joule) (b) The air pressure on our body is equal to Atmospheric pressure. (Atmospheric, Sea bottom, Space) (c) For a given object, the buoyant force in liquids of different density is different . (the same, density, different, area) (d) The SI unit of pressure is N/m 2 . (N/m3, N/m2, kg/m2, Pa/m2) Q. 2 Make a match. A Group B Group 1. Fluid e. Same pressure in all directions 2. Blunt knife a. Higher pressure 3. Sharp needle d. Lower pressure 4. Relative density c. Specific gravity 5. Hecto Pascal b. Atmospheric pressure Q. 3 Answer the following questions in brief. (a) A plastic cube is releas...

 16. The Universe  Exercise Q. 1 Name these: (a) Birth place of stars – Nebula (b) Biggest planet in the solar system – Jupiter (c) The galaxy which is our neighbour – Andromeda (d) Brightest planet in the solar system – Venus (e) Planet with largest number of satellites – Jupiter (f) Planets without a single satellite – Mercury and Venus (g) Planet with a rotation different from other planets – Venus (rotates east to west) (h) A celestial body that carries a tail along – Comet Q. 2 Fill in the blanks. (a) The group of galaxies of which our Milky Way is a part is called the Local Group . (b) Comets are made of ice and dust particles . (c) The planet Uranus appears as if it is rolling along its orbit. (d) Jupiter is a stormy planet. (e) The Pole Star is the best example of a variable type of star. Q. 3 Say whether right or wrong. Correct the wrong statements. (a) Venus is the planet closest to the sun. — Wrong Correct stat...

 15. Fun with Magnets  Exercise Q. 1 How will you do this? (a) Determine whether a material is magnetic or non-magnetic. Take a magnet and bring it near the object. If the object is attracted to the magnet, it is magnetic (for example iron, nickel, cobalt). If it is not attracted, it is non-magnetic . (b) Explain that a magnet has a certain magnetic field. Place iron filings on a sheet of paper and pass a magnet under the paper. The filings arrange themselves along lines that show how the magnetic force acts. These lines indicate the magnet's magnetic field (the space around the magnet where magnetic effects are felt). (c) Find the north pole of a magnet. Suspend the magnet by a thread so it can turn freely. The end which points to the north direction is the magnet’s north pole (N) . Alternatively, bring a compass near the magnet: the north-pointing end of the compass needle (which itself is a small magnet) will be repelled by the magnet’s north pole an...

 14. Light and the Formation of Shadows Exercise Q. 1 Choose an appropriate word and fill in the blanks. (a) A star is a natural source of light. (b) A candle is an artificial source of light. (c) When light passes through a prism, it gets separated into seven colours. (d) The image obtained in the pinhole camera is inverted . (e) A shadow is formed when an opaque object comes in the way of light. (f) When a transparent object comes in the way of light, light passes through it. Q. 2 Write whether the following objects are luminous or non-luminous. Object Luminous / Non-luminous A book Non-luminous A burning candle Luminous A wax cloth Non-luminous A pencil Non-luminous A pen Non-luminous A light bulb Luminous ...

 13. Sound  Exercise Q. 1 Fill in the blanks. (a) The propagation of sound does not occur through a vacuum . (b) Noise pollution is a social issue. (c) The sound which is disagreeable to the ears is called noise . (d) Noise has adverse effects on our health . Q. 2 What should we do? (a) The silencer of a motorcycle is broken. Ans. Get the silencer repaired immediately. Do not use the vehicle unnecessarily and avoid disturbing others. (b) A factory in the surroundings is producing continuous loud noise. Ans. Inform the factory management politely and request noise-control measures. If it continues, report to local authorities. Use ear protection if needed. Q. 3 Answer in your own words. (a) What is meant by vibration? Ans. Vibration is the rapid back-and-forth movement of an object. Sound is produced when an object vibrates. (b) Explain with practical examples how sound is propagated through solids. Ans. Sound travels through solids ...