practical-related

Question 1

why does parallax error occur?

Answer 1

due to incorrect positioning of eyes when taking readings

Question 2

how can we avoid parallax errors?

Answer 2

position eyes such that line of sight is perpendicular to the scale

Question 3

why does zero error occur?

Answer 3

due to imperfect alignment of zero marks between main and smaller scales

Question 4

when does zero error occur?

Answer 4

1. in vernier calipers and micrometer screw gauge where they have a main scale and smaller scale
2. in metre rule when the ‘0 cm’ marking is not exactly at the end of the ruler because of wear and tear.

Question 5

how can we correct zero error that occurs in vernier calipers?

Answer 5

positive zero error (zero mark of vernier scale is slightly to the right of main scale): reading - positive alignment

negative zero error (zero mark of vernier scale is slightly to the left of main scale): reading - negative alignment

Question 6

how can we correct zero error that occurs in micrometer screw gauge?

Answer 6

positive zero error (zero marking on thimble scale below datum line): reading - positive misalignment

negative zero error (zero marking on thimble scale above datum line): reading - negative misalignment

Question 7

how can we correct zero error that occurs in metre rule?

Answer 7

measure from 1 cm marking

Question 8

why does random error occur?

Answer 8

error that is caused by other factors such as human error, environmental conditions, experimental set-up, etc

Question 9

how can we avoid random error?

Answer 9

repeat the measurements a few times and calculate the average value

Question 10

how can we avoid human reaction time error?

Answer 10

reaction time error can sometimes be reduced by using light gates and electronic timing or sensors connected to a computer to record time taken for objects; take average timings