Free Measurements MCQs with Answers

251. The charge on an electron is equal to :

• A. 1.7588×10^19 Coulomb
• B. 1.6022×10^-19 Coulomb
• C. 1.2057×10^19 Coulomb
• D. 0.6022×10^19 Coulomb

Explanation: 1.6022×10^-19 Coulomb: This option is correct. The charge of an electron is approximately -1.6022×10^-19 Coulomb.

252. The SI unit of inductance is:

• A. Weber
• B. Weber meter^-2
• C. Tesla
• D. Henry

Explanation: Henry is the SI unit of inductance, symbolized by the letter H.

253. The angle subtended at the centre of a sphere by its surface area is equal to:

• A. 4/3 π radian
• B. 4/3 π steradian
• C. 4 π radian
• D. 4 π streradian

Explanation: One steradian is the solid angle of a sphere subtended by a portion of the surface whose area is equal to the square of the sphere's radius. The complete surface area of a sphere= 4πr² so the total solid angle about a point = 4πr²/r² = 4π steradian The steradian is the unit of solid angles. It is used in 3D geometry. Whereas the radian is used in planar geometry so options A and C are ruled out as we are dealing with a 3D cone here. (The mention of surface area in the question implies that 3D geometry is involved)

254. A student measures a current as 0.05 A. Which of the following correctly expresses this result?

• A. 50 mA
• B. 50 µA
• C. 500 mA
• D. 500 µA

Explanation: The current of 0.05 A can be expressed as 50 mA because 'milli' means one thousandth, making 0.05 A equivalent to 50 milliamperes. Option A is correct. Option B (50 µA) and Option D (500 µA) are incorrect because microamperes are much smaller than milliamperes. Option C (500 mA) is incorrect because it represents a larger current than 0.05 A.

255. The prefix 'tera' stands for

• A. 104
• B. 109
• C. 10-6
• D. 1012

Explanation: Tera donates multiplication by one trillion or 10¹².OPTION A: The prefix "myria" OPTION B: The prefix "Giga" stands for 10^9.OPTION C: The prefix "micro" stands for 10^-6.

256. Which of the following lists contains scalar quantities only?

• A. Mass, acceleration, temperature, kinetic energy
• B. Mass, volume, electrical potential, kinetic energy
• C. Acceleration, temperature, volume, electric charge
• D. Momentum, electric intensity, density, magnetic flux.

Explanation: A scalar quantity contains only magnitude and no direction, making options B the correct answer. Mass, volume, and electrical potential are all examples of scalar quantities as they can be fully described by their magnitude alone. Kinetic energy is also a scalar quantity due to the mathematical relationship between mass and velocity. Options A, C, and D include vector quantities, such as acceleration, momentum, and electric intensity, which have both magnitude and direction, making them incorrect choices for this question.

257. Which of the following is the unit of pressure?

• A. Kg m s-1
• B. Kg m-1 s-2
• C. Kg m2 s-2
• D. Kg m-2 s-1

Explanation: Pressure is calculated as force per unit area. In this case, the correct unit of pressure is Kg m-1 s-2. This unit is derived from the formula P = F/A, where force is measured in Kg m s-2 and area in m2. This simplifies to Kg m-1 s-2, which is the unit of pressure.Option A is incorrect as it represents the unit of momentum, not pressure. Option C is also incorrect as it represents the unit of energy or work. Option D is not the unit of pressure either.

258. Which of the following is closest to a yard:

• A. 0.01 m
• B. 0.1 m
• C. 1 m
• D. 100 m

Explanation: The correct answer is 1 meter because a yard is approximately 0.9144 meters, making 1 meter the closest option. A yard is a unit of length used in the imperial system, and when converted to the metric system, it measures just under one meter. The other options are either too small (0.01 m and 0.1 m) or too large (100 m) to be considered close to a yard.

259. 1nm x 1km =

• A. 1um
• B. 1mm
• C. 1pm
• D. 1fm

Explanation: 1nm×1km=(10−9m)×(103m)=10−6m21 μm=10−6 m1nm×1km=1μm

260. Which of the following is the correct way of writing units:

• A. 71 Newton
• B. 12mu s
• C. 8 Kg
• D. 43 kg m-3

Explanation: Option d is correct because it follows the standard convention for writing units in the International System of Units (SI).