Exercise Questions | Physics 9th | Chapter 1 | Physical Quantities & Measurements | Balochistan Book

1. Encircle the correct answer.
The number of base units in S.I as
(a) 3 (b) 4 (c) 6 (d) 7
The fundamental unit of time in S.I is
(a) day (b) hour (c) minute (d) second
Which one of the following is not a derived unit?
(a) Newton (b) Watt (c) Metre (d) Pascal
One nanometer is equal to
(a) 〖10〗^(-3) m (b) 〖10〗^(-6) m (c) 〖10〗^(-9) m (d) 〖10〗^(-12) m
One kilogram is equal to
(a) 〖10〗^2 g (b) 〖10〗^3 g (c) 〖10〗^4 g (d) 〖10〗^5 g
The mass of a dust particle is 2.5×〖10〗^(-9) kg. How many such particles will have combined mass equal to 2.5kg?
(a) 〖10〗^3 (b) 〖10〗^6 (c) 〖10〗^9 (d) 〖10〗^12
〖10〗^(-6) seconds is called
(a) desi second (b) milli second (c) micro second (d) nano second
In scientific notation 58000m can be written as
(a) 580×〖10〗^2 m (b) 58×〖10〗^3 m (c) 5.8×〖10〗^4 m (d) 5.8×〖10〗^(-4) m
The least count of a Vernier callipers is equal to
(a) 1cm (b) 0.1cm (c) 0.01cm (d) 0.001cm
The least count of a screw gauge is equal to
(a) 1cm (b) 0.1cm (c) 0.01cm (d) 0.001cm
Which instrument is most suitable to measure the diameter of a thin metallic wire?
(a) screw gauge (b) vernier callipers (c) measuring tape (d) metre rule
The number of significant figures in 23.4506 are
(a) 2 (b) 4 (c) 5 (d) 6
The number of significant figures in 0.0006032 is
(a) 7 (b) 5 (c) 4 (d) 3
Define Physics.
Differentiate between base and derived quantities.
Name the seven base quantities and their SI units.
What is meant by scientific notation?
State the least count of a Vernier callipers in mm and cm.
State the least count of a screw gauge in mm and cm.
What is meant by zero error of an instrument like Vernier callipers or screw gauge?
What are significant figures?
Separate the base quantities and derived quantities from the following list. Length, area, density, time pressure, mass, speed and temperature.
Give names and symbols of the prefixes which represent the following values.
(a) 〖10〗^(-6) (b) 〖10〗^(-3) (c) 〖10〗^3 (d) 〖10〗^6
The zero of Vernier scale lies to the right of the main scale zero of a Vernier callipers (When the jaws are closed). Explain whether you will add or subtract the zero error from the observed readings of instrument.
The volume of a domestic water storage tank is 3.24m^3. Express this volume in units of litre (3240 litres).
Explain why digital stopwatch is preferred over analog or mechanical stopwatch.
What is the importance of the final zeroes in the number without any decimal point?
1. A boy in your class is 1.6m tall, what will be his height in mm and μm?
2. The mass of neutron is 1.675×〖10〗^(-27) kg. Convert it into gram and milligram.
3. The age of girl studying in 9th class is 15 years. Convert her age into seconds and express in scientific notation.
4. Express the following quantities in scientific notation
(a) 5000000000000m (b) 21033000000kg (c) 0.000000102s (d)0.000000000246m
5. Convert the leap year into seconds and express it in scientific notation
6. What is the reading on vernier calipers for the following figure?
7. What is the reading on screw gauge for the following figure?
8. State the number of significant figures in the following measurements.
1. 234567m 2. 2003kg 3. 0.000529s 4. 5.98×〖10〗^24 kg 5. 15.30J
9. Radius of the metallic sphere is 2.35cm. Calculate its volume using formula V=4/3 πr^3 up to reasonable number of significant numbers.
10. Round off the following numbers to three significant figures.
(a) 8.724 (b) 8.725 (c) 8.735 (d) 8.737
11. The volume of a domestic water storage tank is 3.24m^3. Express the volume in units of litre.