Units and Measurements quiz

The SI unit of luminous intensity is:

The dimensional formula of pressure is:

The number of significant figures in 0.00450 is:

[M L^2 T^-2] is the dimensional formula of:

The dimensional formula of angular velocity is:

Which of these is dimensionless?

The SI unit of amount of substance is:

The product 2.5 x 3.42, with the correct significant figures, is:

The number of significant figures in 5.00 x 10^3 is:

The dimensional formula of power is:

Distinguish between fundamental and derived units. (2 marks)

What are supplementary units? Name them. (2 marks)

Why are trailing zeros in a number with a decimal point significant? (2 marks)

State the rule for significant figures in multiplication and division. (2 marks)

Find the dimensional formula of momentum and of impulse. What do you notice? (2 marks)

Check whether s = ut + (1/2)at^2 is dimensionally correct. (2 marks)

Why can dimensional analysis not find numerical constants? (2 marks)

Express 72 km/h in m/s. (2 marks)

Find the dimensional formula of the coefficient of viscosity from F = 6 pi eta r v. (2 marks)

Why does a dimensionally correct equation need not be physically correct? Give an example. (2 marks)

A rectangular sheet is 4.234 m long and 1.005 m wide. Find its area to the correct number of significant figures. (3 marks)

A body of mass 4.237 g has a volume of 2.51 cm^3. Find its density to the correct number of significant figures. (3 marks)

Convert 1 newton into dynes using dimensional analysis. (3 marks)

The speed of a wave on a string depends on the tension T and the mass per unit length mu. Find the formula by dimensional analysis. (3 marks)

State the number of significant figures in 6.032 N/m^2 and in 0.0006032 m^2. (3 marks)

Read the passage and answer the questions. A student measures a cube of mass 5.74 g and side 1.2 cm. (i) Find the volume of the cube. (ii) Find its density. (iii) Round the density to the correct number of significant figures. (5 marks)

Read the passage and answer the questions. A car's speedometer shows 72 km/h. A physics student wants the speed in SI units. (i) Write the SI unit of speed. (ii) Convert the speed into SI units. (iii) Write the dimensional formula of speed. (5 marks)

Read the passage and answer the questions. A teacher writes the formula F = 6 pi eta r v for the viscous force on a sphere. (i) Write the dimensions of F, r and v. (ii) Find the dimensions of eta. (iii) Can dimensional analysis give the constant 6 pi? (5 marks)

Read the passage and answer the questions. A student suggests that the period of a pendulum is T = 2 pi sqrt(g/l). (i) Find the dimensions of sqrt(g/l). (ii) Is the formula dimensionally correct? (iii) Write the correct formula. (5 marks)

Read the passage and answer the questions. Three masses of 436.32 g, 227.2 g and 0.301 g are placed on a balance. (i) Find their total mass without rounding. (ii) Which measurement has the fewest decimal places? (iii) Write the total to the correct precision. (5 marks)

Explain the need for measurement and units. Describe the SI system with its base and supplementary units. (6 marks)

State the rules for determining the number of significant figures in a measured quantity, with examples. (6 marks)

Explain the rules for rounding off and for arithmetic operations with significant figures. (6 marks)

What are dimensions and dimensional formulae? Write the dimensional formulae of velocity, acceleration, force, work, power and pressure. (6 marks)

Explain the three main uses of dimensional analysis with one example each. (6 marks)