# Units and Dimensions practice paper for class 11

This article is about Units and Dimensions practice paper for class 11 physics. These are a set of 10 questions which you can use as a practice test after completing your chapter. You can print this article. Try to complete these questions in one hour time frame.

## Units and Dimensions practice paper

Question 1 Write three physical quantities having dimensions $[ML^2T{-2}]$.                            (1)

Question 2 If $g$ is the acceleration due to gravity and $\lambda$ is wavelength , then which physical quantity does $\sqrt{\lambda g}$ represents.                                                   (1)

Question 3 What are the dimensions of $a$ and $b$ in the relation if $F=a+bx$ where $F$ is force and $x$ is distance.                                        (1)

Question 4 What do you understand by absolute error?                          (1)

Question 5 State the principle of homogeneity of dimensions. Test the dimensional homogeneity of the following

$h=h_0 + v_0 t+\frac{1}{2}gt^2$                                        (2)

Question 6 Show that the maximum fractional error in the product of two quantities is equal to the sum of fractional errors in the individual quantities.                                 (2)

Question 7 How is random error eliminated? What do you mean by

(i) relative error

(ii) percentage error

(iii) mean absolute error                                             (5)

Question 8 A planet moves around the sun in nearly circular orbit. Its period of revolution $T$ depends upon

(i) radius $r$ of the orbit

(ii) mass $M$ of the sun

(iii) the gravitational constant $G$

show dimensionally that $t^2 \propto r^3$

Question 9 A new system of units is proposed in which unit of mass is $\alpha$ Kg, unit of length $\beta$ m and unit of time is $\gamma$ s. How much will 5 J measure in this new system. $[5J=\alpha^{-1} \beta^{-2} \gamma^{2}$

Question 10 In an experiment refractive index of glass was observed to be 1.45, 1.56, 1.54, 1.44, 1.54 and 1.53. Calculate

(i) mean value of refractive index

(ii) Mean absolute error

(ii) Fractional error

(iv) percentage error

Express he result in terms of absolute error and percentage error.