Magnetic flux (in weber) in a closed circuit of resistance 20 Ω varies with time t ( s ) as φ=8 t2-9 t+5. The magnitude of the induced current at t =0.25 s will be mA

Question

Magnetic flux (in weber) in a closed circuit of resistance 20 Ω varies with time t ( s ) as φ=8 t2-9 t+5. The magnitude of the induced current at t =0.25 s will be mA (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

φ=8 t2-9 t+5 e m f=-(d φ/d t)=-(16 t-9) At t =0.25 s Emf =-[(16 × 0.25)-9]=5 V Current =( text Emf / text Resistance )=(5 V /20 Ω) =(1/4) A =(1000/4) mA =250 mA

Q. Magnetic flux (in weber) in a closed circuit of resistance $20 Ω$ varies with time $t (s)$ as $ϕ = 8 t^{2} - 9 t + 5$ . The magnitude of the induced current at $t = 0.25 s$ will be ______ $m A$

$ϕ = 8 t^{2} - 9 t + 5$
$e m f = - \frac{d ϕ}{d t} = - (16 t - 9)$
At $t = 0.25 s$
$E m f = - [(16 \times 0.25) - 9] = 5 V$
Current $= \frac{Emf}{Resistance} = \frac{5 V}{20Ω}$
$= \frac{1}{4} A = \frac{1000}{4} m A = 250 m A$

Q. Magnetic flux (in weber) in a closed circuit of resistance 20Ω varies with time t(s) as ϕ=8t2−9t+5. The magnitude of the induced current at t=0.25s will be ______mA

ϕ=8t2−9t+5 emf=−dtdϕ​=−(16t−9) At t=0.25s Emf=−[(16×0.25)−9]=5V Current = Resistance Emf ​=20Ω5V​ =41​A=41000​mA=250mA

Q. Magnetic flux (in weber) in a closed circuit of resistance $20 Ω$ varies with time $t (s)$ as $ϕ = 8 t^{2} - 9 t + 5$ . The magnitude of the induced current at $t = 0.25 s$ will be ______ $m A$

$ϕ = 8 t^{2} - 9 t + 5$
$e m f = - \frac{d ϕ}{d t} = - (16 t - 9)$
At $t = 0.25 s$
$E m f = - [(16 \times 0.25) - 9] = 5 V$
Current $= \frac{Emf}{Resistance} = \frac{5 V}{20Ω}$
$= \frac{1}{4} A = \frac{1000}{4} m A = 250 m A$