True or False

1. Magnetic poles exist in pairs.
2. Magnetic field increases as we go away from the magnet.
3. Magnetic lines of force always cross each other.
4. Electric generator is used to generate current.
5. Magnetic field has magnitude as well as direction.
6. In India, the frequency of A.C. is 50 Hz.
7. In a domestic electric circuit, electrical appliances are connected in parallel to each other.
8. A split ring commutator is used in a D.C. generator & in an electric motor.
9. Electromagnetic induction was discovered  by Coulomb.
10. Permanent electromagnets are usually made of soft iron.
11. The Frequency of an alternating current is zero.
12. In a domestic circuit, the main fuse is placed in the path of the livewire.
13. In Fleming’s right hand rule, the thumb shows the direction of the induced current.
14. The magnetic field in the hollow space in a solenoid is very weak.
Answer : 1. True.    2. False (Magnetic field decreases as we go away from the magnet)
          3. False, (Magnetic lines of force never cross each other). 4. True 5. True. 6. True. 7. True. 8. True. 9. False, (Electromagnetic induction was discovered by Faraday & independently by Henry). 10. False (Permanent electromagnets are not made from soft iron.). 11. False. (The frequency of a direct current is zero.) 12. True. 13. False, (In Fleming’s right hand rule, the middle finger indicates the direction of the induced current.) 14. False, (The magnetic field in the hollow space is a solenoid is very strong).



1. Substances which are bitter to taste are acids.
2. Beet root is a natural indicator.
3. Litmus paper is obtained from a plant lichen.
4. Methyl orange is an olfactory indicator.
5. The strength of Base is represented by pH.
6. The pH of rainwater is 7.
7. Carbon dioxide is non metallic oxide.
8. Lime water with butter can cure acidity.
9. Electrolysis of fused sodium chloride liberates hydrogen at the cathode.
10. When sodium bicarbonate is heated, it releases carbon dioxide.
11. Salt of strong acid & weak base are acidic with the pH value less than 7.
12. Washing soda is used to refine petroleum.
13. Chlorine is a strong disinfectant.
14. Alkalies have H+ ions.
15. On heating or exposure to air, salts lose water of crystallization & turn into substance which is termed as anhydrous substance.
Answer   1. False (Substances which are bitter to taste are bases)
              2. True,            3. True,            4. False(Methyl orange is a synthetic indicator.) 
              5. False(Strength of base is represented by pOH.),       
              6. False (pH of rainwater is less than 7.),   7. True,       8. True,   
              9. False(Electrolysis of fused sodium chloride liberates sodium at the cathode),    
              10. True,     11. True,        12. True,         13.True, 
              14. False(alkalies have OH ions),  15. True,





true or false, science true and false, find true or false,

2 comments:

Subscribe to: Posts (Atom)