Q25 / 68 · NTA Abhyas (JEE Main) 2020 · Physics · Electromagnetic Induction

In given figure, a wire loop has been bent so that it has three segments ab (a quarter circle), bc (a square corner) & ca (straight line). Here are three choices for a magnetic field through the loop -

Figure

(1) B→1=3i^ + 7j^ – 5tk^

(2) B→2=5ti^ – 4j^ – 15k^

(3) B→3=2i^ –5tj^ – 12k^

Where B is in milli tesla and t is in second. If the induced current in the loop due to B1→,B2→,B3→ are i1, i2, i3 respectively then -

  • A
    i1> i2> i3
  • Correct answer
    B
    i2> i1> i3
  • C
    i3 > i2 > i1
  • D
    i1=i2=i3

Solution

i1=dϕ1dt 1R=dB1×AreaRdt=ddt 5t×πa24×1R=5πa24R

i2=dϕ2dt×1R=d5a2tdt×1R=5a2R

i3=dϕ3dt×1R=d0.5a2dt× 1R=a22R

∴ i2 > i1 > i3

Hence, the correct answer is option: 'B'.

More Electromagnetic Induction Questions