Units and Measurement Questions and Answers Part-11

1. One femtometer is equivalent to
a) \[10^{15} m\]
b) \[10^{-15} m\]
c) \[10^{-12} m\]
d) \[10^{12} m\]

Answer: b
Explanation: One femtometer is equivalent to \[10^{-15} m\]

2. How many wavelength of \[Kr^{86} \] are there in one metre
a) 1553164.13
b) 1650763.73
c) 652189.63
d) 2348123.73

Answer: b
Explanation: According to the definition

3. Which of the following pairs is wrong
a) Pressure-Baromter
b) Relative density-Pyrometer
c) Temperature-Thermometer
d) Earthquake-Seismograph

Answer: b
Explanation: Pyrometer is used for measurement of temperature.

4. Select the pair whose dimensions are same
a) Pressure and stress
b) Stress and strain
c) Pressure and force
d) Power and force

Answer: a

5. Dimensional formula \[ML^{-1}T^{-2} \]  does not represent the physical quantity
a) Young's modulus of elasticity
b) Stress
c) Strain
d) Pressure

Answer: c

6. Dimensional formula \[ML^{2}T^{-3} \]  represents
a) Force
b) Power
c) Energy
d) Work

Answer: b

7. The dimensions of calorie are
a) \[ML^{2}T^{-2}\]
b) \[MLT^{-2}\]
c) \[ML^{2}T^{-1}\]
d) \[ML^{2}T^{-3}\]

Answer: a
Explanation: Calorie is the unit of heat i.e., energy. So dimensions of energy = ML2T-2

8. Whose dimensions is \[ML^{2}T^{-1}\]
a) Torque
b) Angular momentum
c) Power
d) Work

Answer: b
Explanation: Angular momentum = mvr = MLT-1 * L = ML2T-1

9. If C and R represent capacitance and resistance respectively, then the dimensions of RC are
a) \[M^{0}L^{0}T^{2}\]
b) \[M^{0}L^{0}T\]
c) \[ML^{-1}\]
d) None of the above

Answer: b

10. Dimensions of one or more pairs are same. Identify the pairs
a) Torque and work
b) Light year and wavelength
c) Energy and Young's modulus
d) Both a and b

Answer: d
Explanation: [Torque] = [work] = [ML2T–2]
[Light year] = [Wavelength] = [L]