If ₁₀ 7=0.8451 , then the position of the first significant figure of 7⁻²⁰ is

Step-by-step solution

We have, aligned & ₁₀ 7=0.8451 & Let x=7⁻²⁰ & x=-20 7=-20 0.8451=-16.902 & x=10^ -16.902 aligned Now, -16.902 lies between -16 and -17 So, position of first significant figure of 7⁻²⁰ is 17 .