# Class 9 Physics Physical Quantities and Measurement 10. A measuring cylinder (fig 1.31) is filled with 500 \mathrm{cc} water. A stone of mass 20 \mathrm{~g} is immersed in to the cylinder such that water level rises up to 800 \mathrm{cc} . Which s

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##### 10. A measuring cylinder (fig 1.31) is filled with 500 \mathrm{cc} water. A stone of mass 20 \mathrm{~g} is immersed in to the cylinder such that water level rises up to 800 \mathrm{cc} . Which statement is correct?a) The difference between the readings gives the density of stone.b) The difference between the readings gives volume of the stonec) The final reading gives the density of stoned) The final reading gives the volume of stone

1.6 What role SI units have played in the development of science?

iii. Amount of a substance in terms of numbers is measured in:(a) gram(b) kilogramme(c) newton(d) mole

5. A chips wrapper is 4.5 \mathrm{~cm} long and 5.9 \mathrm{~cm} wide. Its area upto significant figures will bea) 30 \mathrm{~cm}^{2} b) 28 \mathrm{~cm}^{2} c) 26.55 \mathrm{~cm}^{2} d) 32 \mathrm{~cm}^{2}

1.6 On closing the jaws of a Vernier Callipers zero of the vernier scale is on the right to its main scale such that 4th division of its vernier scale coincides with one of the main scale division. Find its zero error and zero correction.

ii. Which one of the following unit is not a derived unit?(a) pascal(b) kilogramme(c) newton (d) watt

1.11 Why do we need to measure extremely small interval of times?

4. An engineer measures the width of an aluminum sheet using Vernier caliper as shown in fig 1.29 a)What is the measurement of the width of aluminum sheetb)Which gives more precise measurement Vernier caliper Screw Gauge or meter rule?Fig 1.29

1. The Figure 1.26 shows part of a Vernier scale what is the reading on the Vernier scalea) 6.50 \mathrm{~cm} b) 6.55 \mathrm{~cm} c) 7.00 \mathrm{~cm} d) 7.45 \mathrm{~cm}

3. An object of mass 100 \mathrm{~g} is immersed in water as shown in the figure 1.27 what is the density of the material from which object is made?a) 0.4 \mathrm{gcm}^{3} b) 0.9 \mathrm{gcm}^{3} c) 1.1 \mathrm{gcm}^{3} d) 2.5 \mathrm{gcm}^{3} Fig 1.27

1.8 Which of the following quantities have three significant figures?(a) 3.0066 \mathrm{~m} (b) 0.00309 \mathrm{~kg} (c) 5.05 \times 10^{-27} \mathrm{~kg} (d) 301.0 \mathrm{~s}

5. A pendulum swings as shown if figure 1.30 from X to Y and back to X againi) What would be the most accurate way of measuring time for one oscillation? with the help of a Stop Watch.a) Record time for 10 oscillations and multiply by 10b) Record time for 10 oscillation and divide by 10c) Record time for one oscillationd) Record time from X to Y and double it

1.2 How do the prefixes micro nano and pico relate to each other?

10. Length mass electric current time intensity of light and amount of substance are examples ofa) basequantitiesb) derived quantitiesc) prefixesd) quartile quantities

5. A pendulum swings as shown if figure 1.30 from X to Y and back to X againii) Suggest an instrument for measuring time period more accurately.

EXAMPLE 1.2Find the diameter of a wire using a screw gauge.

9. Find the density of wood as sphere and cube if the mass of wood is 1 \mathrm{~kg} .Is there any change in density due to shape?

1 . \begin{tabular}{|l|l|}\hline \multicolumn{1}{|c|}{ Column A Action } & Column B Branch \\\hline Cooking Bar B.Q & Thermodynamics \\\hline Turning the Bulb on & \\\hline Riding a bicycle & \\\hline Looking for Giant Galaxies & \\\hline Producing a loud sound & \\\hline Describing an atom & \\\hline Obtaining energy from Earth & \\\hline\end{tabular}

7. All accurately known digits and first doubtful digit in an expression are known asa) non-significant figuresb) significant figuresc) estimated figuresd) crossed figures

4. What is the reading of this micrometer in figure 1.28 a) 5.43 \mathrm{~mm} b) 6.63 \mathrm{~mm} c) 7.30 \mathrm{~mm} d) 8.13 \mathrm{~mm} Fig 1.28

iv. An interval of 200 \mathrm{u} \mathrm{s} is equivalent to(a) 0.2 \mathrm{~s} (b) 0.02 \mathrm{~s} (c) 2 \times 10^{-4} \mathrm{~s} (d) 2 \times 10^{-6} \mathrm{~s}

6. write the correct prefix of notiona) 75000 \mathrm{~m}=750 b) 2 / 1000 \mathrm{sec}=1 c) 1 / 1000000 \mathrm{~g}=1 d) 1000000000 \mathrm{~m}=1

Convert mass of an electron 9.11 \times 10^{31} \mathrm{~kg} into standard form.

1.3 Pick out the base units in the following:joule newton kilogramme hertz mole ampere metre kelvin coulomb and watt.

6. A worldwide system of measurements in which the units of base quantities were introduced is calleda) prefixesb) international system of unitsc) hexadecimal systemd) none of above

8. A wooden piece is made in different shapes take length (\mathrm{l})=\operatorname{radius}(\mathrm{r})=2 \mathrm{~m} Calculate its volume as \mathrm{a} :a) Sphereb) Cubec) Cylinderd) Pyramide) Cylinder

1.1 Encircle the correct answer from the given choices.i. The number of base units in SI are:(a) 3(b) 6(c) 7(d) 9

What is the mass a solid iron wrecking ball of radius 18 \mathrm{~cm} . if the density of iron is 7.8 \mathrm{gm} / \mathrm{cm}^{3} ?

1.2 What is the difference between base quantities and derived quantities? Give three examples in each case.