The magnetic flux through a surface varies with time as follows: φ=12t2+7t+3 Here φ is in milliweber and t is in seconds. The induced emf at t = 5s ?

Question

The magnetic flux through a surface varies with time as follows: φ=12t2+7t+3 Here φ is in milliweber and t is in seconds. The induced emf at t = 5s ? (A) 338 mV (B) 127 mV (C) 105 mV (D) None of these

Tardigrade Admin · Accepted Answer

E = - (d φ/dt) = 24 t + 7 At t = 5s , E = 24 × 5 + 7 = 127 mV

Q. The magnetic flux through a surface varies with time as follows :
$ϕ = 12 t^{2} + 7 t + 3$
Here $ϕ$ is in milliweber and t is in seconds. The induced emf at t = 5s ?

338 mV

127 mV

105 mV

None of these

$E = - \frac{d ϕ}{d t} = 24 t + 7$ At $t = 5 s$ , $E = 24 \times 5 + 7 = 127 mV$

Q. The magnetic flux through a surface varies with time as follows : ϕ=12t2+7t+3 Here ϕ is in milliweber and t is in seconds. The induced emf at t = 5s ?