Free Measurements MCQs with Answers

181. The standard of time in SI system is the clock of:

• A. Uranium
• B. Rubidium
• C. Cesium
• D. Radium

Explanation: The definition of a second in the SI system is based on the properties of cesium atoms. It's determined by the frequency of radiation that cesium atoms emit when transitioning between two specific energy levels. This consistent and precise measurement of atomic vibrations forms the basis for the standard unit of time, ensuring worldwide uniformity and accuracy.

182. One Angstrom equals:

• A. 10-8 cm
• B. 108 m
• C. 10-6 m
• D. 108 mm

Explanation: As centi is equal to 10-2,10-8 × 10-2 m = 10-10 mWhich is equal to one angstrom.

183. 10 Giga hertz is equivalent to:

• A. 1010 Hz
• B. 109 Hz
• C. 107 Hz
• D. 10-10 Hz

Explanation: As Giga is equal to 10⁹ therefore,10 × 10⁹ Hertz = 10¹⁰ HertzHence, this option is correct.

184. Which of the following is the unit of electrical energy?

• A. Kg m/s2
• B. Dyne
• C. kWh
• D. Joules / sec

Explanation: Kilowatt-hour (kWh) is indeed a unit of electrical energy. It's commonly used to measure the amount of energy consumed or produced over time and is the standard unit for billing electricity usage.

185. One Newton is equal to:

• A. 102 dynes
• B. 103 dynes
• C. 104 dynes
• D. 105 dynes

Explanation: One Newton is equal to 10^5 dynes in the CGS (centimeter-gram-second) system of units.

186. The unit of dimensions of which of the following pairs of physical quantities are identical?

• A. Impulse and Momentum
• B. Stress and Strain
• C. Pressure and Density
• D. Gravitational potential and Energy

Explanation: Both impulse and momentum have the same unit of dimensions. Impulse is defined as force multiplied by time, while momentum is the product of mass and velocity. Both quantities share the unit of dimensions [mass] × [velocity], which is equivalent to [force] × [time], demonstrating their similarity in units.

187. The dimensions of impulse are the same as that of:

• A. Energy
• B. Work
• C. Power
• D. Momentum

Explanation: Explanation of this question will be added soon!

188. 0.0084 has _ significant figures.

• A. 2
• B. 4
• C. 5
• D. 1

Explanation: Significant figures are the meaningful digits in a number that indicate its precision. In 0.0084, the 8 and the 4 are considered significant because they contribute to the number's value. Zeros before the first non-zero digit (here, the 8) are not significant; they just indicate the decimal's placement. Therefore, in 0.0084, only the 8 and the 4 are considered significant figures.

189. The _ sciences deal with the properties and behavior of non-living things.

• A. Natural
• B. Social
• C. Physical
• D. Biological

Explanation: The best fit for the properties and behavior of non-living things among these options would be C) Physical Sciences as it specifically deals with the properties and behavior of non-living entities like matter and energy.

190. The people of _ were the pioneers of decimal system.

• A. China
• B. Indus valley
• C. Euphrates
• D. Egypt

Explanation: The decimal system, which is based on powers of ten, is attributed to the ancient civilization of Indus Valley. This numerical system involves using digits from 0 to 9 and organizing them in a positional value system, where the value of a digit depends on its position within a number.