# Online Assessment Class XI

**Assessment No – 1 | Units and Measurements**

**1.** What will be the value of 100 N in a system having 50 cm, 250 g and 1 minute as fundamental units of length, Mass and time respectively? **(3)**

**2.** The true value of a quantity is 2.89 m. Two students P and Q perform experiments to find its value. The result of the experiment performed by P and Q are 2.598 m and 2.1345 m respectively. Which one is accurate and which one is precise? **(2)**

**3.** A physical quantity Q is given by Q=A^{2}B^{1/2}C^{-4}D^{-1/2}. The percentage error in A, B, C and D are 1%, 2%, 4% and 2% respectively. Find the percentage error in Q. **(3)**

**4. **What do you mean by Significant figures? Give the number of significant figures in the following numbers (i) 45.009 (ii) 2 Dozen Banana (iii) 3.09 x 10^{-8} iv) 640 **(3)**

**5. **The measure of the diameter of a cylinder is (1.60±0.01) cm and its length is (5.0±0.1) cm. Calculate the percentage error in its volume. **(3)**

**6. **Distinguish between accuracy and precision.** (2)**

**7. **Assuming that the mass ‘m’ of the largest stone that can be moved by a flowing river depend upon the velocity ‘v’ of the river, the density ‘ρ’ of water and the acceleration due to gravity ‘g’. Derive the formula for mass ‘m’ using dimensional analysis. **(3)**

**8. **If E, M, J and G respectively denotes energy, mass, angular momentum and gravitational constant. Calculate the dimensions of EJ^{2}/M^{5}G^{2}. **(1)**

**Please Submit Final Answers**