The number of significant figures in 1.050 × 10³ is:

Solution

Physics sir · 4 steps

In scientific notation, count only the digits before the power of ten, every single one of them.

1. Ignore the power. The factor 10³ only tells you where the decimal point sits. It never adds or removes significant figures, so look at 1.050 alone.
2. Check each digit. The 1 and the 5 are non-zero, so they count. The 0 between them is sandwiched between non-zero digits, so it counts too.
3. The trailing zero. The last 0 comes after the decimal point. A trailing zero to the right of a decimal point is significant, because it was written on purpose to show the measurement is precise to that place.
4. So. All four digits 1, 0, 5, 0 are significant, so the answer is 4, option (c).

The idea to keep. The power of ten never changes the count. Zeros between non-zero digits always count, and trailing zeros after a decimal point always count.

Answer from the NTA final answer key. Solution by PrepWiser.