Units & Dimensions

⏱ Time: 0s

Q1. The unit of energy in the CGS system is: (2020)

Solution:

In the CGS system, the unit of energy is Erg, where 1 Joule = 10^7 Ergs.

⏱ Time: 0s

Q2. If the speed of light is 3 x 10^8 m/s, what is its value in km/s? (2021)

Solution:

To convert m/s to km/s, divide by 1000. Therefore, 3 x 10^8 m/s = 3 x 10^5 km/s.

⏱ Time: 0s

Q3. Which of the following quantities is not a scalar? (2021)

Solution:

Velocity is a vector quantity as it has both magnitude and direction, while mass, temperature, and speed are scalar quantities.

⏱ Time: 0s

Q4. The unit of energy equivalent to 1 Joule is: (2023)

Solution:

1 Joule is defined as 1 kg·m²/s² and also equals 1 N·m, hence both are correct.

⏱ Time: 0s

Q5. Which of the following is the correct dimensional formula for frequency? (2021)

Solution:

Frequency has the dimensional formula [M^0 L^0 T^-1].

⏱ Time: 0s

Q6. Which of the following quantities has no dimensions? (2019)

Solution:

Angle is a pure number and has no dimensions, while force, energy, and pressure all have dimensions.

⏱ Time: 0s

Q7. What is the unit of work in the SI system? (2023)

Solution:

The SI unit of work is Joule (J).

⏱ Time: 0s

Q8. Which of the following is the unit of pressure? (2023)

Solution:

The unit of pressure is Pascal (Pa), which is equivalent to N/m².

⏱ Time: 0s

Q9. What is the base unit of temperature in the SI system? (2020)

Solution:

The base unit of temperature in the SI system is Kelvin (K).

⏱ Time: 0s

Q10. If the mass of an object is measured in kilograms and its volume in cubic meters, what is the unit of density? (2022)

Solution:

Density is defined as mass per unit volume, so the unit of density is kg/m³.