# 11 - Electromagnetic Induction Questions Answers

Joshi sir comment
Joshi sir comment
Joshi sir comment
Joshi sir comment
Joshi sir comment

SIR ANSWER IS given as C could u pls explain?

Joshi sir comment

Two Magnets of M magnetic dipole moment are placed shown in figure. What will be the intensity of magnetism at the point P shown in figure.

Joshi sir comment

the resultant dipole moment is √2M  thus  the resultant magnetic  field is  μ2√2M/4πd3   (ans)

A SIMPLE ELECTRIC MOTOR HAS AN ARMATURE RESISTANCE OF 1 ohm & RUNS FROM A D.C SOURCE OF 12V . IT DRAWS A CURRENT OF 2A WHEN UNLOADED . WHEN A CERTAIN LOAD IS CONNECTED TO IT ,IT SPEED REDUCES BY 10% OF ITS INITIAL VALUE ,THE CURRENT DRAWN BY THE UNLOADED MOTOR IS??

ANS 3A

Asked By: SARIKA SHARMA 15 Day ago

SIR , ISTHE FOLLOWG METH. IS CORRECT

R=1ohm , E=12V , I=2A

I=(E-e)/R => e=10 ON PUTTING D VALUES

NOW AS IT IS REDUCES BY 10% MEANS NOW e' = 9V ( 10/100 X 10 = 1 CHANGE , THUS FINAL = 10-1=9)

I= E-e'/R = ( 12-9)/ 1 = 3A (RESISTANCE IS KEPT CONST.) RESISTANCE WILL CHANGE OR NOT??

SARIKA SHARMA 15 Day ago

Joshi sir comment

yes this method is correct.

in the previous case if north pole is brought near the mettalic ring  why the direction is reversed. we have to consider the  drn of magnetic field of magnet or not. if yes then which drn N-S or S-N.

Joshi sir comment

If observer is in the side of magnet, then in the given case form N in the ring, it will give you anticlockwise direction.

Due to this current produced magnetic field will be towards the coming magnet, and since north pole of magnet is coming towards ring so this field will oppose the motion of magnet