Units and Measurement- Grade 11

The number of significant figures in 3.80 m is

• 1

• 2

• 3

• 4

Which of the following is false regarding significant

figures ?

• All non-zero digits are significant.

• The zeros appearing in the middle of a number are significant while those at the end of a number without a decimal

  point are ambiguous.

• The powers of 10 are counted while counting the number

  of significant figures.

• Greater the number of significant figures in a measurement, smaller is the percentage error.

Which of the following measurements is the most

accurate ?

• $9\times10^{-2}m$

• 
  

  $90\times10^{-2}m$

• $900\times10^{-2}m$
  

• $0.090\times10^{-2}m$
  

The length of a cube is $2.1\times10^{-2}\ m$ . The volume in significant figures will be

•  $9.2×10^{-6}\ m$ 
  

•  $9.3\times10^{-6}\ m$  
  

•  $9.26\times10^{-6}\ m$  

•  $9.261\times10^{-6}\ m$  

The length l, breadth b and thickness t of a block of wood were measured with the help of a measuring scale. The results with permissible errors are

l = 15.12 ± 0.01 cm, b = 10.15 ± 0.01 cm,

t = 5.28 ± 0.01cm.

The percentage error in volume upto proper significant

figures is

• 0.28%

• 0.36%

• 0.48%

• 0.64%

In an experiment, we measure quantities a, b and c.
Then x is calculated from the formula :

 $x=\frac{ab^2}{c^3}$  
The percentage errors in a, b, c are ±1%, ±3%, and ±2% respectively. The percentage error in x can be

• ±1%
  

• ±12%

• ±3%

• ±13%

The pressure on a square plate is measured by measuring the force on the plate and the length of the sides of the plate by using the formula

 $P=\frac{F}{l^2}$  
If the maximum errors in the measurement of force and length are 4% and 2% respectively, then the maximum error in the measurement of pressure is

• 1%
  

• 2%

• 8%

• 10%

The focal length of a mirror is given by  $\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$  
where u and v represent object and image distances
respectively. The maximum relative error in f is

•  $\frac{\Delta f}{f}=\frac{\Delta u}{u}+\frac{\Delta v}{\upsilon}$  

•  $\frac{\Delta f}{f}=\frac{1}{\Delta u/u}+\frac{1}{\Delta v/v}$  

•  $\frac{\Delta f}{f}=\frac{\Delta u}{u}+\frac{\Delta\nu}{\upsilon}-\frac{\Delta\left(u+v\right)}{u+\nu}$  

•  $\frac{\Delta f}{f}=\frac{\Delta u}{u}+\frac{\Delta\nu}{\upsilon}+\frac{\Delta u+\Delta v}{u+v}$