Free Measurements MCQs with Answers

201. 0.0046 can be written in scientific notation as:

• A. 4.6 x 10^-3
• B. 4.6 x 10^-2 cm
• C. 460 x 10
• D. 46 x 10^-2

Explanation: To express 0.0046 in scientific notation, we want to represent it as a number between 1 and 10 multiplied by a power of 10.0.0046 can be written as 4.6 × 10-3 in scientific notation. This form indicates that 4.6 multiplied by 10-3 gives 0.0046.

202. In the following, the smallest quantity is:

• A. 6.653 Km
• B. 0.635 Km
• C. 6.35 x 10^4 m
• D. 0.635 x 10^8 mm

Explanation: Comparing these values, the smallest quantity among the options is (0.635) kilometers, which corresponds to option B.

203. 6 x 10^-12 / 2 x 10^-6 will be equal to:

• A. 3 x 10^6
• B. 3 x 10^18
• C. 3 x 10^12
• D. 3 x 10^-6

Explanation: The given question is 6×10-12 / 2×10-6. We divide the integers and powers of ten separately. 6/2 = 3 whereas 10-12 / 10-6 = 10-6. Hence the answer is 3 × 10-6.

204. The density of air is 1.2 kg/m3. It can be expressed in g/cm3 by:

• A. 1.2 x 10^6
• B. 1.2 x 10^3
• C. 1.2 x 10^-6
• D. 1.2 x 10^-3

Explanation: To convert kg to g we will multiply by 1000. To convert cm to m we divide by 100 so, to convert cm3 to m3 we will divide by 1003 = 1000000.1.2 x 1000 = 12001200 / 1000000 = 0.0012 0.0012 = 1.2 x 10-3

205. The pressure of 106 dyne cm-2 is equivalent of _ in SI:

• A. 105 Nm-2
• B. 104 Nm-2
• C. 106 Nm-2
• D. 107 Nm-2

Explanation: 1 dyne per square centimeter (dyn/cm²) is equivalent to 0.1 pascal (Pa) in the International System of Units (SI).Therefore, 10⁶ dyn/cm² is equivalent to 10⁶ × 0.1 Pa or simply 10⁵ Pa or N/m² in SI units.

206. The present international standard of time is:

• A. 1/84,400 of means solar day
• B. 9192631770 vibrations of cesium atom
• C. 1/60th of minute
• D. 1/3156 x 10^7 of a year

Explanation: The present international standard of time, as measured by atomic clocks, is defined by the exact number of vibrations or oscillations of the cesium atom's electrons. It's specifically defined as 9,192,631,770 vibrations of the cesium atom's electrons in a second. This precise measurement forms the basis of the current definition of the second in the International System of Units (SI).

207. Supplementary S.I units of radian and steradian were established to measure

• A. Geometrical quantities
• B. Luminous intensity
• C. Electric current
• D. Temperature

Explanation: his is correct. The radian and steradian are indeed used to measure specific geometrical concepts:Radian: measures plane angles.Steradian: measures solid angles

208. The option that shows three base quantities' units in System International (SI) is

• A. Gram, joule, and second.
• B. Gram, centimetre, and dyne.
• C. Kilogram, metre, and second.
• D. Kilogram, newton, and second.

Explanation: The correct answer is Option C: 'Kilogram, metre, and second'. These are the base units in the SI system for the fundamental quantities of mass, length, and time. Option D is incorrect because 'newton' is a derived unit of force. Options A and B list units that are either derived or belong to the CGS system, which are not considered SI base units.

209. The least count of a metre scale is

• A. 0.001 cm.
• B. 0.1 mm.
• C. 1 mm.
• D. 1 cm

Explanation: The least count of a measuring instrument is the smallest measurement that can be accurately read. For a standard meter scale, the smallest division is 1 millimeter (mm), making the least count 1 mm. Option A, 0.001 cm, suggests an unrealistic precision not possible with a regular meter scale. Option B, 0.1 mm, is also not achievable with a typical meter scale. Option D, 1 cm, is too large to be the least count, as meter scales have finer divisions.

210. The option that shows three base quantities' units in System International (S.I.) is

• A. Gram, joule and second.
• B. Gram, centimetre and dyne.
• C. Kilogram, metre and second
• D. Kilogram, newton and second,

Explanation: The correct answer is Option C:kilogram, metre and second. These are the base units in the SI system for mass, length, and time, respectively. Option D is incorrect because although kilogram and second are base units, newton is not; it is a derived unit. Options A and B list units from the CGS system and include joules and dynes, which are also derived units.