NEET Practice Questions (MCQs) with Answers & Solutions

$$ Resistance R = { V \over I} $$ ${ \triangle R \over R } = { \triangle V \over V } + { \triangle I \over I } $ $ { \triangle R \over R } = { 5 \over 100} + { 0.3 \over 10 } $ $ { \triangle R \over R } = { 8 \over 100} $ $ { \triangle R \over R } \% = 8 \% $

In the number 0.000150, the significant figures are the digits that carry meaning contributing to its measurement resolution. Leading zeros are not counted as significant. Hence, the significant figures are '1', '5', and '0', which total to 3 significant figures.

A number has four significant figures if it has four digits that contribute to its precision. In the number 1.011, all four digits ('1', '0', '1', '1') are significant as they contribute to the precision of the number.

In the number $5.50 imes 10^3$, the significant figures are determined by the digits in the coefficient (5.50 in this case), not the exponent. The digits '5', '5', and '0' are all significant, making a total of 3 significant figures.

The number 500.5000 has 7 significant figures. All the digits including the trailing zeros after the decimal point are considered significant.

When adding numbers, the result should be reported with the same number of decimal places as the number with the least decimal places. Here, 15.225 cm (3 decimal places), 7.21 cm (2 decimal places), and 3.0 cm (1 decimal place) are added. Therefore, the result should have 1 decimal place: 15.225 + 7.21 + 3.0 = 25.435 cm, which rounds to 25.4 cm.

When performing operations with significant figures, the result should have the same number of significant figures as the value with the least number of significant figures. In the expression $(2.30 + 4.70) imes 10^5$, both 2.30 and 4.70 have 3 significant figures. The sum is 7.00, which also has 3 significant figures. Therefore, the number of significant figures in the result is 3.

The radius of the circle is 1.26 cm, which has 3 significant figures. When calculating the area using the formula $A = ext{πr}^2$, we must ensure the result is expressed with the same number of significant figures as the radius. $A = ext{π} imes (1.26)^2 ightarrow A ≈ 4.9850 cm^2$. Rounding this to 3 significant figures, we get $4.98 cm^2$.