A square loop of side 10 cm and resistance 0.7Ω is placed vertically in east-west plane. A uniform magnetic field of 0.20 T is set up across the plane in north east direction. The magnetic field is decreased to zero in 1 s at a steady rate. Then, magnitude of induced emf is x×10−3 V. The value of x is ______.
Answer: 2
Solution
The loop (area A=0.1×0.1=0.01 m2) lies in the east-west (vertical) plane, so its normal points north-south. The field B=0.2 T points north-east, i.e. at 45∘ to the loop's normal.
Effective flux-linked field component =Bcos45∘=20.2.
emf=ΔtΔΦ=tA⋅Bcos45∘=10.01×0.2/2=10002 V=2×10−3 V
So x=2.
Key confirmed: 2.
JEE Main · 2024 · 29 Jan 2024 · Shift 1 · Integer answer
