Question

The external and internal radius of a hollow cylinder are measured to be $(4.23 \,\pm \,0.01)\, cm$ and $(3.89 \,\pm \, 0.01) \,cm$, respectively. The thickness of the wall of the cylinder is

• A. $(0.34 \,\pm \,0.02)\, cm$
• B. $(0.17 \,\pm \,0.02)\, cm$
• C. $(0.17 \,\pm \,0.01)\, cm$
• D. $(0.34 \,\pm \,0.01)\, cm$

Answer 1

Answer: (A)

$(0.34 \,\pm \,0.02)\, cm$

Answer 2

Thickness of wall $(t) = r, - r_2$ $t = 4.23 - 3.89 = 0.34\, cm$ $\Delta t = \pm (\Delta r_1 + \Delta r_2) = (0.01 + 0.01) = 0.02\, cm$ $\therefore$ Thickness of wall $=( t \pm \Delta t) = (0.34 \pm 0.02) \,cm$