1. Polishing of the surfaces in contact beyond a limit increases friction because: i)irregularities are increased ii)surface projections are sharpened iii)area of actual contact is increased iv)none of these My ans. (ii) 2. A chain is placed on a frictionless table such that 1/5 part is hanging down over the edge of the table. If the length of the chain be 'l' and mass be m, then the work done in pulling up the hanging part of the chain back on the table is _________ My ans. (mgl/5) 3. A bottle filled with water at 30 degree celsius and fitted with a cork is taken to the moon. If the cork is opened at the surfacce of the moon then- water will freeze. Am I right? 4. A body of mass 2kg slides down on a curved track which is a quadrant of a circle of radius 1 meter. All the surfaces are frictionless, if the body starts from rest, its speed at the bottom of the track is __________ My calculation :4.43 m/sec 5. The bob of a simple pendulum of length 'l' is negatively charged. A positively charged metal plate is placed just below it and the pendulum is made to oscillate. Then what will be the effecton the time period? My answer: No effect. 6. Tank containing water has an orifice in one verticle side. If the centre of orfice is 4.9 m below the surface level in the tank, the volcity of discharge is- Ans: 9.8 m/sec 7. The magnetism in a magnet is mainly due to: i) the orbital motion of the electrons ii) the spin motion of the electrons iii) the nuclear charge iv) none of these 8. Solar spectrum is a band spectrum. True or false? Ans: True. 9. A faulty balance is in equilibriumwhen its pans are empty. A body weighs 100 gf and 121 gf on the two pans. Then its actual guess will be _____ My ans: 110 gf 10. Magnifying power of a simple microscope can be increased if we use an eyepiece of higher focal length. true or false? Please tell me whether I am right, some suggestions etc. You can answer for any question you know. Thanks in advance!!