Units and Measurements Mock Test – Class 11 Physics

1. A calculation gives . Rounded to two significant figures, it should be written as

2. The radius of a circle is measured with a percentage error of . Since its area is , the percentage error in area is

3. Consider the following statements about SI base quantities.
I. Amount of substance has the unit .
II. Luminous intensity has the unit .
III. Electric current has the unit .
The valid statements are

4. A mass is recorded as . Its value in is

5. Four length readings are , , , and . The arithmetic mean is

6. A quantity has dimensional formula . Its value is in a system with base units , , and . In a new system, the base units are , , and . The new numerical value is

7. A vernier callipers has least count . For a small cylinder, the main scale reading is , the vernier division coincides, and the zero error is . The corrected diameter is

8. The SI base-unit form of is

9. For estimating the thickness of one sheet of paper using an ordinary scale, a better method is to

10. The expression is dimensionally suitable for a time period because

11. Relative error has no unit because it is formed by

12. A reported length means that the measurement is best read as

13. A speed is measured as with a maximum uncertainty of . Expressed in , the speed and uncertainty are

14. For a vernier callipers, vernier scale divisions coincide with main scale divisions. If main scale division is , the least count is

15. A periodic event repeats times in . Its frequency is

16. A machine does of work in . The power developed is

17. A formula contains the constant factor , as in . If only is measured, the uncertainty in comes from

18. A sphere has volume . If the percentage error in is , the percentage error in is

19. A length is measured with two instruments: Instrument P has least count , and Instrument Q has least count . For the same careful procedure, Instrument Q is generally better because it

20. A proposed relation is , where and are lengths and is time. The dimensional formula of must be

21. A screw gauge has pitch and circular scale divisions. A wire gives main scale reading , circular scale reading , and zero error . If the wire length is , the volume of the wire in , using , is closest to

22. In the relation , is velocity and is displacement. The dimensional formula of is

23. A measured value is reported as . The quantity represents

24. A physical quantity is given by . If , , and , the maximum percentage error in is

25. Dimensional analysis can be used to

26. The relation is dimensionally consistent with energy because

27. A graph has velocity on the vertical axis and time on the horizontal axis. The dimension of the slope is

28. The proposed relation , where and are velocities, is acceleration, and is displacement, is dimensionally invalid because has dimensions

29. A parallax measurement uses a baseline of . When the baseline is doubled while observing the same distant object, the parallax angle approximately

30. A laboratory note says, “The mass of the object is .” If the same mass is expressed in , the numerical value becomes

31. A record gives rules for maximum percentage error.

The row that needs repair is

32. The group containing only fundamental physical quantities from the usual mechanics starting set is

33. A vernier callipers has least count . The main scale reading is , and the seventh vernier division coincides with a main scale mark. The observed reading is

34. The expression can appear in a physical relation only if

35. A lab report gives the following final result for a measured length: . The better reported form is

36. The dimensional formula of acceleration follows from . It is

37. A set of five readings for a time interval is , , , , and . The mean value is

38. Complete the statement: A physical quantity expressed as has as the ______ and as the ______.

39. For a difference , the maximum absolute error is

40. A container has mass when full and when empty. The mass of the contents with maximum absolute error is

41. A balance reads even when its pan is empty. This error is mainly

42. When the jaws of a vernier callipers are closed, the vernier zero lies to the right of the main scale zero. This situation indicates

43. A proposed equation is , where is energy, is mass, is velocity, is force, and is displacement. The equation fails dimensional homogeneity because

44. A dimensional check is applied to , where is displacement, is velocity, is acceleration, and is time. The equation fails because

45. Consider the following statements.
I. Length, mass, and time can be used as fundamental quantities in mechanics.
II. Density is derived because it uses mass and volume.
III. Time is derived from speed and length in the basic classification of quantities.
The valid statements are

46. A diameter is measured as with an uncertainty of . A length is measured as with an uncertainty of . The comparison of percentage errors is

47. A scale is read from a position not perpendicular to the mark, so the same observer consistently reads the value too high. This is mainly

48. A force acts through a displacement in the direction of force. The work is later divided by time to get power. The power and maximum percentage error are

49. A scale list is arranged from smaller to larger length as

50. If random error is reduced by taking many readings, the final result should still include