#### Nature of Physical World and Measurement Important Questions

11th Standard

Reg.No. :
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Physics

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. Which of the following has the highest number of significant figures?

(a)

0.007 m2

(b)

2.64 x 1024kg

(c)

0.0006032 m2

(d)

6.3200 J

2. If $\pi=3.14,$ then the value of ${\pi}^{2}$ is

(a)

9.8596

(b)

9.860

(c)

9.86

(d)

9.9

3. The velocity of a particle v at an instant t is given by v = at + br2. The dimensions of b is

(a)

[L]

(b)

[LT-1]

(c)

[LT-2]

(d)

[LT-3]

4. Which is deals with the study of materials of an intermediate length scale.

(a)

Macroscopic physics

(b)

Macroscopic physics

(c)

Microscopic physics

(d)

All the above

5. What is the range of astronomical time scales to microscopic scales

(a)

1015S to 10-15S

(b)

109S to 10-18S

(c)

1018S to 10-22S

(d)

1011S to 10-16S

6. 5 x 2 = 10
7. Having all units in atomic standards is more useful. Explain.

8. When the planet Jupiter is at a distance of 824.7 million kilometers from the earth. its angular diameter is measured to be 35.72 of arc. Calculate the diameter of Jupiter.

9. Two resistances RI = (100 ± 3) $\Omega$, R2 = (150 ± 2)$\Omega$, are connected in series. What is their equivalent resistance?

10. The length and breadth of a rectangle are (5.7 ± 01.) cm and (3.4 ± 02.) cm respectively. Calculate the area of the rectangle with error limits.

11. State the number of significant figures in the following 0.0006032

12. 5 x 3 = 15
13. What are the advantages of the SI system?

14. Give any three practical units of time.

15. Find the dimensions of a and b in the formula $\left[ P+{{a\over V^2}} \right][V-b]=RT$ where P is pressure and V is the volume of the gas

16. Show that $({P}^{-5/6}{ρ}^{1/2}{E}^{1/3})$ is of the dimension of time. Here P is the pressure, $ρ$ is the density and E is the energy of a bubble)

17. The mass and volume of a body are found to be 4$\pm$0.03 kg and 5$\pm$0.01 m3 respectively. Then find the maximum possible percentage error in density.

18. 4 x 5 = 20
19. The length of a rod as measured in an experiment was found to be 3.48m, 3.46m, 3.49m, 3.50m and 3.48 m. Find the average length, the absolute error in each observation and the percentage error.

20. If the value of universal gravitational constant in SI is 6.6$\times$10-11 Nm-2 kg-2,then find its value in CGS System.

21. The shadow of a pole standing on a level ground is found to be 45 m longer when the sun's altitude is 30o than when it was 60o. Determine the height of the pole.[Given $\sqrt { 3 }$=1.73]

22. The frequency of vibration of a string depends of on, (i) tension in the string (ii) mass per unit length of string, (iii) vibrating length of the string. Establish dimensionally the relation for frequency.