Question

The staff reading at a distance of 80m from a level with the bubble at its center is 1.52 m and when the bubble moved 5 divisions out of the center, the reading is 1.6 m. the angular value of 1 division of bubble is

• A. 25.05 sec
• B. 20.62 sec
• C. 41.25 sec
• D. 14.53 sec

Answer 1

The correct option is C 41.25 sec


$S\to$ Difference between the two readings.

$S=b-a$

$=1.6-1.52$

$=0.08m.$

$L\to$ Distance between level and staff

$L=80m$

$n\to$ no. of division bubble moves

$n=5$

$\therefore Sensitivity,\varphi \to Angularvalueof1divisionofbubble$

$\varphi =\frac{s}{L\times n}radians$

$=\{\left(\frac{0.08}{80\times 5}\right)\times \frac{180}{\pi }\times 60\times 60\}sec$

$=41.25sec.$