D. Long Answer Type Questions
wys
the method of your choice.
with an example.
1. With the help of an activity explain how will you measure the length of a curved line. Use
2. What do you understand by the term 'parallax error'? How can this be rectified? Explain
3. What precautions will you take to measure the length of the table-top accurately?
Answers
Answer:
1.Tie a knot at one end of the thread. Place the thread at the beginning of the line and try to measure a small initial portion of the line which is relatively straight. Place your thumb at the other end of the measured portion and measure next straighter portion. Repeat the above step till the end of line is reached.
2.It is defined as the shift in the apparent position of an object due to the different position of viewing. The error is usually noticed by observing the nearby abject with one of the eye closed while watching from the other eye. ... It is occurred on the line of sight and is usually removed by careful observation
3.You must take the following precautions while using various instruments for measuring length : The scale should be place along the length to be measured. Your eye must be in front of and in line where the measurement is to be taken. Ensure that the ends of the scale are not worn-out.
Explanation:
A curved line or surface cannot be measured by a straight scale, a measuring tape or thread must be used instead.To measure a curved line using a thread, follow the below steps:
Tie a knot at one end of the thread.
Place the thread at the beginning of the line and try to measure a small initial portion of the line which is relatively straight.
Place your thumb at the other end of the measured portion and measure next straighter portion.
Repeat the above step till the end of line is reached. Make a knot at the end of the line.
Now, straighten the thread and measure the length of the two knots on a scale.