JEE MainPhysicsMathematics in Physics
A student measures the resistance, diameter, and length of a wire to determine its electrical resistivity. The measured values are: Resistance, R = (10.0 0.1) , Diameter, d = (2.00 0.02) mm Length, l = (50.0 0.5) cm The maximum percentage error in the calculated value of resistivity is:
Options
- A3
- B2
- C4
- D5
Correct answer
C. 4
Step-by-step solution
The formula for the electrical resistivity of a wire is given by: = R A l = R ( d^2 / 4) l The maximum fractional error in resistivity is the sum of the fractional errors of the individual quantities (with the power of d bringing a factor of 2): = R R + 2 d d + l l Calculating the individual percentage errors: Percentage error in R = ( 0.1 10.0 ) 100 = 1 % Percentage error in d = ( 0.02 2.00 ) 100 = 1 % Percentage error in l = ( 0.5 50.0 ) 100 = 1 % Substituting these into the error equation: Maximum percentage err