Single correct · +4 / −1
The number of significant figures in 0.00250 is:
- (a) 2
- (b) 3
- (c) 5
- (d) 6
Answer and solution
Answer (b) 3
Solution
Physics sir · 4 steps
Start counting at the first non-zero digit, then keep every digit after it, trailing zero included.
- Leading zeros. The zeros in 0.00 before the 2 only mark where the decimal point sits. They carry no measured information, so they are not significant.
- Trailing zero. The final 0 comes after a non-zero digit and to the right of the decimal point. Someone wrote it on purpose to show the value is known to that place, so it is significant.
- Check in scientific notation. Write it as 2.50 × 10⁻³. The leading zeros vanish into the power of ten, and the digits left are 2, 5 and 0.
- So. The number 0.00250 has 3 significant figures, which is option (b).
The idea to keep. Rewrite the number in scientific notation. Every digit left in the front part is significant: leading zeros disappear, and a trailing zero after a decimal point stays.
Answer from the NTA final answer key. Solution by PrepWiser.