Free Measurements MCQs with Answers

221. 1 joule is equal to:

• A. 104 ergs
• B. 105 ergs
• C. 106 ergs
• D. 107 ergs

Explanation: One Joule is the amount of work done when a force of 1 newton displaces a mass through a distance of 1 meter in the direction of the force applied. One joule = Nm (SI ) One joule = 107 ergs (CGS) Hence, D is the correct option

222. 1 light year distance is:

• A. Distance travelled by earth in one year
• B. Distance travelled by star in one year
• C. Distance travelled by light in one year
• D. Distance travelled by light in one galactic year

Explanation: The following is the solution:Option C is correct since it gives the right definition of one light year.Option A is incorrect since it gives simply the distance of earth in orbit.Option B is incorrect since it gives simply the distance travelled by the star in space.Option D is incorrect since one galactic year is equal to 230 million light-years. The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the centre of the Milky Way Galaxy.

223. All of the following are equivalent to watt except:

• A. (Amperes)2ohm
• B. Joules/ sec
• C. Amperes x volts
• D. Amperes/volt

Explanation: Power is measured in watts. P = I x V (power is current times voltage) and it is NOT current divided by voltage. So, A/V can't be equivalent to watt and hence, option D is correct.

224. The principle of homogeneity of dimensions determines:

• A. Only the variables in the equation
• B. Only the constants in the equation
• C. The correctness of an equation
• D. Both constants and variables in the equation

Explanation: The principle of homogeneity of dimensions states that for an equation to be dimensionally correct, every term must have the same dimensions on both sides. This principle helps verify the correctness of an equation rather than focusing on individual variables or constants. Option C is correct because it aligns with this principle by ensuring equations are valid through dimensional consistency. Options A, B, and D are incorrect because they focus on specific elements rather than the equation's overall dimensional integrity.

225. The dimensions of pressure is:

• A. A
• B. B
• C. C
• D. D

Explanation: The following is the solution:𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 𝐹𝑜𝑟𝑐𝑒/𝐴𝑟𝑒𝑎By dimensional analysis: 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 𝑘𝑔. 𝑚. 𝑠−2/𝑚2 Therefore, by simplification we get out answer:[MLT−2]/[L2]=ML-1T-2The correct dimension of pressure: [MLT−2]/[L2]=ML-1T-2

226. The time period 'T' of a simple pendulum depends on its length 'l' and acceleration due to gravity 'g' using unit dimensions. The correct equation for the time period is:

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: T=2πgl The period of a simple pendulum is given by T = 2 gl, where l is the length of the pendulum and g is the acceleration due to gravity. The time period is directly proportional to length and inversely proportional to gravity.

227. An observer notes the reading of scale from different angles (parallax) while measuring the length of the wire, what type of error is possible:

• A. Systematic error
• B. Zero error
• C. Precise error
• D. Random Error

Explanation: Parallax error is due to the positioning of the eye while recording a value. The positioning and the error in the reading birthed from this positioning is completely random since the inaccurate reading could be either greater or lesser than the true value.

228. Force in terms of base units is expressed as:

• A. Kg ms-2
• B. Kgm2s-2
• C. Kgm2s-3
• D. None of these

Explanation: According to Newton's 2nd lawF=maWhere F is force , m is mass and a is acceleration . The unit of mass is 'kg' and the unit of acceleration is 'm/s2' .The units of F will be,F=kgm/s2F=kgms-2

229. Which one is the highest power multiple?

• A. Giga
• B. Tera
• C. Mega
• D. Deca

Explanation: The correct answer is Tera, as it represents 1012, the largest power of ten among the options. Giga represents 109, Mega represents 106, and Deca represents 101. Therefore, Tera is the highest power multiple here.

230. SI unit of charge is _.

• A. Ampere
• B. Volt
• C. Coulomb
• D. Calorie

Explanation: The correct answer is Coulomb, which is the SI unit used to measure electric charge. The other options are units for different physical quantities: Ampere for electric current, Volt for electrical potential difference, and Calorie for energy.