Question

An electormagnetic flow meter is used to measure the average flow rate of an effluent in a pipe of diameter $40mm$. The velocity profile is symmetrical and can be assumed unifrom. The flux density in the liquid has a peak value of $0.2Wb/m^2$. If the output from the flowmeter electrode is recorder as $0.4V$ peak to peak. Then the average velocity of the effluent in the pipe is ____ $m/sec$

• A. $25$
• B. $30$
• C. $20$
• D. $50$

Answer 1

The correct option is A $25$

$\text{Peak to peak voltage at flow meter output}=0.4V$

$\text{Peak voltage at flow meter output}=\frac{0.4}{2}=0.2V$

$\therefore \text{Average flow rate}$

$v=\frac{E_0}{B\times L}=\frac{0.2}{0.2\times 40\times {10}^{-3}}$

$=25m/sec$