Units and Measurements
Test 3

Correct answer Carries: 4.

Wrong Answer Carries: -1.

The dimensional formula of power is:

Power is the rate at which work is done: \( P = \frac{W}{t} \).

Since work has the formula \([ML^2T^{-2}]\) and time is \([T]\), the dimensional formula of power is \([ML^2T^{-3}]\).

\([ML^2T^{-3}]\)
\([MLT^{-2}]\)
\([M^2L^2T^{-4}]\)
\([ML^3T^{-2}]\)
1

Which of the following is a fundamental quantity?

Fundamental quantities are those that cannot be derived from others — like mass, length, and time.

Velocity
Force
Time
Pressure
3

The SI unit of solid angle is:

Solid angle is measured in steradians (sr), a dimensionless unit in the SI system.

Radian
Steradian
Degree
Gradian
2

Which one of the following pairs has different dimensions?

Pressure and stress both share the same dimensional formula \([ML^{-1}T^{-2}]\), but energy has \([ML^2T^{-2}]\).

Force and Weight
Pressure and Stress
Work and Energy
Pressure and Energy
4

If the unit of length is doubled, how is the unit of area affected?

Area is proportional to the square of length. So, if the unit of length doubles, the unit of area becomes four times larger.

Doubled
Halved
Four times
Remains unchanged
3

Which of the following has the dimensional formula \([M^0L^0T^0]\)?

Dimensionless quantities like refractive index, strain, and angles have no physical dimensions.

Strain
Force
Velocity
Pressure
1

The physical quantity with the same dimensions as impulse is:

Impulse is the product of force and time, having the formula \([MLT^{-1}]\), which matches momentum.

Work
Energy
Power
Momentum
4

The SI unit of electric current is:

Electric current’s SI base unit is the ampere (A).

Coulomb
Volt
Ampere
Ohm
3

The number of significant figures in \( 2.0030 \) is:

All non-zero digits and any zeros between or after significant digits in decimal form are significant.

3
4
5
6
3

Which of the following quantities is dimensionless?

Reynolds number is a pure ratio and has no physical dimensions.

Viscosity
Reynolds number
Acceleration
Force
2

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