JEE Main · 2026 · 23 Jan 2026 · Shift 1 · Electromagnetic Induction

A 20 m long uniform copper wire held horizontally is allowed to fall under the gravity (

g = 10 m / s^{2}

) through a uniform horizontal magnetic field of 0.5 Gauss perpendicular to the length of the wire. The induced EMF across the wire it travells a vertical distance of 200 m is ______ mV.

(A) $0.2 10$
(B) $2010$ ✓ Correct
(C) $210$
(D) $20010$

Answer: (B)

Solution

After falling

h = 200

m the wire moves with speed

v = 2 g h = 2 \times 10 \times 200 = 2010

m/s. With

B = 0.5

gauss

= 0.5 \times 1 0^{- 4}

T and length

ℓ = 20

m mutually perpendicular to

v

and

B

, the motional emf is

ε = B v ℓ = (0.5 \times 1 0^{- 4}) (2010) (20) = 2010 \times 1 0^{- 3}

= 2010

mV.

JEE Main · 2026 · 23 Jan 2026 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Electromagnetic Induction →

More JEE Main questions on Electromagnetic Induction

XPQY is a vertical smooth long loop having a total resistance R where PX is parallel to QY and separation between them is $l$ . A constant magnetic field B perpendicular to the plane of the loop exists in the entire space. A rod CD of length L ( $L > l$ ) and mass $m$ is made to sli …
JEE Main 2026View solution →
Three identical coils $C_{1}, C_{2}$ and $C_{3}$ are closely placed such that they share a common axis. $C_{2}$ is exactly midway. $C_{1}$ carries current $I$ in anti-clockwise direction while $C_{3}$ carries curre …
JEE Main 2026View solution →
Inductance of a coil with $1 0^{4}$ turns is 10 mH and it is connected to a dc source of 10 V with internal resistance of $10Ω$ . The energy density in the inductor when the current reaches $(\frac{1}{e})$ of its maximum value is …
JEE Main 2026View solution →
Figure shows the circuit that contains three resistances ( $9Ω$ each) and two inductors (4 mH each). The reading of ammeter at the moment switch $K$ is turned ON, is ______ A.
JEE Main 2026View solution →
A conducting circular loop is rotated about its diameter at a constant angular speed of $100 rad / s$ in a magnetic field of 0.5 T perpendicular to the axis of rotation. When the loop is rotated by $3 0^{\circ}$ from the horizontal position, the induced EMF is 15 …
JEE Main 2026View solution →
A capacitor C is first charged fully with potential difference of $V_{0}$ and disconnected from the battery. The charged capacitor is connected across an inductor having inductance L . In t s $25%$ of the initial energy in the capacitor is transferred to the induct …
JEE Main 2026View solution →