− | [http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-I-SSS-EM-2.pdf Tamilnadu Textbook Class - IX - Chapter - 14 - Measuring Instruments] | + | |[http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-I-SSS-EM-2.pdf Tamilnadu Textbook Class - IX - Chapter - 14 - Measuring Instruments] |