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← JEE Main 2026 · 6 Apr · Shift 1
PhysicsSingle correct+4 / -1Question 26 of 75

JEE Main 2026 · 6 Apr · Shift 1, Physics question 26

The density ρ\rho of a uniform cylinder is determined by measuring its mass mm, length ll and diameter dd. The measured values of mm, ll and dd are 97.42±0.0297.42\pm0.02 g, 8.35±0.058.35\pm0.05 mm and 20.20±0.0220.20\pm0.02 mm, respectively. Calculated percentage fractional error in ρ\rho is ________.

Choose one option
Answer and worked solution

Official answer: B

Density. ρ=4mπd2l\rho=\dfrac{4m}{\pi d^2l}, so
Δρρ=Δmm+Δll+2Δdd=0.0297.42+0.058.35+0.0420.20.\frac{\Delta\rho}\rho=\frac{\Delta m}m+\frac{\Delta l}l+2\frac{\Delta d}d=\frac{0.02}{97.42}+\frac{0.05}{8.35}+\frac{0.04}{20.20}.

Numbers. 0.00021+0.00599+0.00198=0.00820.00021+0.00599+0.00198=0.0082, or 0.82%.

(B)