i. The number of base units in SI is?




... Answer is (c) 7
 A base unit is a unit adopted for the measurement of a base quantity. The System of International (SI) consists of seven base units including meter, kilogram, second, ampere, Kelvin, mole, and candela (The units of the Base Quantity length, mass, time, electric current, temperature, amount of substance and luminous intensity respectively).


ii. Which one of the following units is not a derived unit?




... Answer is (b) kilogram
A kilogram is a base unit for the measurement of the base quantity Mass, while the other pascal, newton, and watt are derived units.


iii. Amount of a substance in terms of numbers is measured in?




... Answer is (d) Mole
 In SI units amount of a substance is the base quantity and is measured in moles.


iv. An interval of 200 µs is equivalent to?




... Answer is (c) 2 x 10 ⁻⁴ s
Solution: 200 µ s = 2 x 10² x 10⁻⁶ s = 2 x 10⁻⁴ s ....... Ans


v. Which one of the following is the smallest quality?




... Answer is (d) 5000 ng
 Solution: 0.01 g = (1 / 100 ) g 2 mg = (2 / 1000 ) g 100 µg = (1 / 10000 ) g 5000 ng = (5 / 1000000) g (as 1 nino "n"= 10⁻⁹), So the smallest value is 5000 ng.


vi. Which instrument is the most suitable to measure the internal diameter of a test tube ?




... Answer is (b) Vernier calipers
 Vernier Caliper has both internal and external jaw. The Internal jaws of a Vernier are used to measure the inner diameter of a hollow tube or cylinder, while the outer jaws are for to measure the outer diameter of substances like a sphere.


vii. A student claimed the diameter of a wire as 1.032 cm using Vernier Callipers up to what extent do you agree with it ?:




... Answer is (c) 1.03cm
 A Vernier caliper has the least count of 0.01 cm (2 decimal places). So we can measure diameter only up to 2 decimal places i.e 1.03. Therefore reading as 1.032 cm is impossible. V = 60 cm/sec.


viii. A measuring cylinder is used to measure ?




... Answer is (c) volume
 A measuring cylinder is a laboratory equipment used to measure the volume of a liquid.


ix. A student noted the thickness of the glass sheet using a screw gauge. On the main scale, it reads 3 divisions while the 8th division on the circular scale coincides with the index line. Its thickness is:




... Answer is (b) 3.08 cm
Solution: The main scale reading Screw gauge = 3 mm, Coinciding division of Circular Scale = n = 8, Least count of screw gauge = 0.01 mm. Thickness of wire = Main scale reading + n × Least Count = 3 + 8 × 0.01=3.08 mm



VIP Note: If you have Learned the above MCQs, then examine yourself by taking this Simple MCQS Quiz (Click here to play the Quiz)


 
Unit 1: Physical Quantities and Measurement
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9th Class MCQs Quizzes LIST

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