Verified Solution • 2025–26 Session
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QJEEM20Phd617: JEE Main 2020 Physics - Class 12 JEEM20Phd617 Solution: A small bar magnet is moved through a coil at constant speed…
A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil? 
Three positions shown describe :
(a) the magnet's entry
(b) magnet is completely inside and
(c) magnet's exit.
Three positions shown describe :
(a) the magnet's entry
(b) magnet is completely inside and
(c) magnet's exit.
Multiple Choice Options
- A https://ik.imagekit.io/novatra/photos/f61345b09cd946bc0ccb9e1585e10ca36695ab257bff78efc1241f62b55db921.webp
- B https://ik.imagekit.io/novatra/photos/180aa0681422bfcb27d4624b042bbcc80a08a5df8511fc11a4c02dfbae0e0441.webp
- C https://ik.imagekit.io/novatra/photos/c1b2cd025e2ed5fcaa856581e3dd21fbe59be37617f4754532e2063502b4799f.webp
- D https://ik.imagekit.io/novatra/photos/27e178427910297bf034f2db2ec7a4e9a43a4a6962ab2c31a32a953ddd2e3f4e.webp
Step-by-Step Verified Solution
When bar magnet is entering with constant speed, flux will change and an e.m.f. is induced, so galvanometer will deflect in positive direction.
When magnet is completely inside, flux will not change, so reading of galvanometer will be zero.
When bar magnet is making on exit, again flux will change and on e.m.f. is induced in opposite direction to not of (a), so galvanometer will deflect in negative direction.
When magnet is completely inside, flux will not change, so reading of galvanometer will be zero.
When bar magnet is making on exit, again flux will change and on e.m.f. is induced in opposite direction to not of (a), so galvanometer will deflect in negative direction.