W=MB(cosθ1−cosθ2)
When it is rotated by angle 180o then θ1=0∘ and θ2=180∘
W=2MB
W=2(NIA)B
=2×250×85×10−6[1.25×2.1×10−4]×85×10−2
=9.1μJ
A 250-Turn rectangular coil of length 2.1cm and width 1.25cm carries a current of 85μA and subjected to a magnetic field of strength 0.85T. Work done for rotating the coil by 180∘ against the torque is:
Held on 30 Apr 2017 · Verified 9 Jul 2026.
9.1μJ
4.55μJ
2.3μJ
1.15μJ
Sign in to track your attempts and accuracy.
Sign in to keep a private note on this question. Nothing you write is ever public.
Two point charges +2μC and -2μC are placed 10 cm apart. The electric field at the midpoint is:
A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is :- 
The electric potential at distance r from a point charge q is V = q/(4πε₀r). The electric field E is:
To an ac power supply of 220 V at 50 Hz , a resistor of $20 \Omega$, a capacitor of reactance $25 \Omega$ and an inductor of reactance $45 \Omega$ are connected is series. The corresponding current in the circuit and the phase angle between the current and the voltage is, respectively-
A wire of resistance R is cut into 8 equal pieces. From these pieces two equivalent resistances are made by adding four of these together in parallel. Then these two sets are added in series. The net effective resistance of the combination is :
Work through every NEET UG Electromagnetism PYQ, year by year.