Tuesday, 28 April 2015

Physics for competitive exams–1

1. Parsec is a measure of   - Astronomical distance

2. The blue colour of the water in the sea is due to    Scattering of blue light by water molecules

3. Galvanized iron is coated with a thin coating of    - Zinc

4. In the visible spectrum the colour having the shortest wavelength is   – Violet

5. The unit of power is  - Joule per second and watt both

6. The heater element in an electric iron is made of   – Nichrome

7. If woolen cloth of red colour is seen in the light of a mercury vapour lamp, then the cloth will appear  – Black

8. At sun rise or at sun set, the sun appears to be reddish while at midday it looks white. This is because of  Scattering due to dust particles an air molecules causes this phenomenon

9. The radiant energy of the sun results from  Nuclear fusion

10. A microscope, in which maximum magnification is achieved, but the object cannot be seen by eye, is called
                                                             – Electron microscope

11. The image formed on the retina of the eye is  real and inverted

12. The transverse nature of light is shown by  Polarization of light

13. The surface of water in a lake is just going to freeze. What is the temperature of water at the bottom  - 40 C

14. Out of water, glycerin, alcohol, air and coal tar - which one is the most viscous medium    – coal tar

80. A double convex air bubble in water would behave as a   - Divergent lens

16. Railway tracks are banked on curves so that    - Necessary centripetal force may be obtained from the horizontal component of the weight of the train
17. The density of water is maximum at  - 40C

18. Oil rises up the wick in a lamp because   - Of the surface tension phenomenon

19. An ice cube contains an iron ball in it and floats in water contained in a vessel. What will happen if the ice melts away   - The water level will go down

20. Which of the following utilizes Newton’s third law of motion?   - Space –rocket

21. The function of cement in masonry (stonework) is based on the phenomenon of    - Adhesion

22. The main sources of heat is  - The sun

23. Transmission of heat by the movement of heated particles is called  - Convection

24. The air becomes heated by  - Convection

25. In a thermos flask, a warm substance remains warm because  - No heat neither enters into nor leaves the inside of the thermos flasks by any of the three methods of transmission conduction, convection and radiation

26. To a space traveler on the moon during day time the lunar sky appears  - Black

27. At which temperature do the reading of the Centigrade and the Fahrenheit scale coincide  -  -400 C

28. Sound is a form of  - Energy

29. Lightning is observed earlier than the sound is heard, because  - Light travels faster than sound

30. The instrument connected with the recording and reproduction of sound is called  - Gramophone

31.  A mirage is the result of   - Increase in the refractive index of the atmosphere with height

32. The dense mass of small water drops on smoke or dust particles in the lower layers of the atmospheres  - Fog

33. A person can not see objects clearly which are nearer than 75 cm from his eyes. What disease is he suffering from
  - Hypermetropia (long-sightedness)

34. a man can not see clearly beyond 10 meters. What disease is he suffering from - Myopia (shortsightedness)

35. A pond of clear water appears less deep than it really is. This is due to - Refraction

36. An earth satellite is kept moving in its orbit. It is due to the phenomenon of centripetal force provided by              
   - The gravitational attraction of the earth on the satellite

37. The speed of light was first measured by - Romer

38. The phenomenon of radio activity is associated with  - Decay of the nucleus
39. When water freezes its density  - Decreases

40. A ‘Celsius’ is a unit     - Equivalent to degree centigrade

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