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A fan of metal blades of length 0.4 m ro...

A fan of metal blades of length 0.4 m rotates normal to a magnetic field of `4xx10^(-3)`T. If the induced emf between the centre and edge of the blade is 0.02 V, determine the rate of rotation of the blade.

Text Solution

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Given : The length of metal blade of fan `l=0.4.`
Magnetic field `B=xx10^(-3)T`
Induced emf between the centre and edge of the blade e = 0.02 V
Rotational area of the blade `A=pi^(2)`
`=3.14xx0.4xx0.4m^(2)`
To find :
Rate of rotation of the blade `omega=?`
`e=NABomegasintheta[theta=90^(@)because" fan rotates normal to a magnetic field "]`
Formula :
`e=NABomega[sintheta=1]" "" No of turns = 1 "`
Solution :
`omega=(e)/(AB)=(0.02)/(3.14xx.4xx.4xx4xx10^(-3))`
`omega=(2)/(200.96)xx10^(3)`
`omega=9.95"revolution"//"second."`
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