# 39 - Magnetism Questions Answers

**Asked By: LUFFY**

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**Joshi sir comment**

$Magnetictorque=\overrightarrow{M}\times \overrightarrow{B}=i\overrightarrow{A}\times \overrightarrow{B}\phantom{\rule{0ex}{0ex}}Torqueduetogravityaboutthepointof\phantom{\rule{0ex}{0ex}}circumference=\overrightarrow{R}\times m\overrightarrow{g}\phantom{\rule{0ex}{0ex}}Nowcomparethetwo$Inform for any issue

SIR ANSWER IS given as C could u pls explain?

**Asked By: AYUSH PAINE**

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**Joshi sir comment**

**Asked By: AYUSH PAINE**

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**Joshi sir comment**

${X}_{C}=50\Omega and{X}_{L}=100\Omega areinparallel.\phantom{\rule{0ex}{0ex}}Resul\mathrm{tan}tis100\Omega capaci\mathrm{tan}ce.\phantom{\rule{0ex}{0ex}}Now100\Omega capaci\mathrm{tan}ceand100\Omega induc\mathrm{tan}cegivereac\mathrm{tan}ce0\Omega \phantom{\rule{0ex}{0ex}}andresis\mathrm{tan}ceis100\Omega .SoonlyoptionDiscorrect.$

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.

**Asked By: BONEY HAVELIWALA**

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**Joshi sir comment**

the resultant dipole moment is √2M thus the resultant magnetic field is μ2√2M/4πd^{3} (ans)

CALCULATE THE MAGNETIC FIELD AT THE CENTRE OF SQUARE WIRE OF SIDE (2)^{1/2}cm AND CARRYING A CURRENT OF 10A.?

**Asked By: GAUTAM SAGAR**

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**Joshi sir comment**

method given by BONEY is correct but formula is not correct

it should be **B = 4×{ (μ _{0}I) / 4πR } × [sinθ_{1}+ Sinθ_{2}]**

two short magnets of equal dipole momet M are fastened perpedicularat their centre.the magnitude of magnetic feild at adistance d from the centre on the bisector of right angles is?

**Asked By: AKANKSHA**

**Solved By: SARIKA**

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**Joshi sir comment**

the resultant dipole moment is √2M thus the resultant magnetic field is μ2√2M/4πd^{3} (ans)

this answer is given by sarika and is correct answer

is impedence as same as resistanace in a circuit // and // are capacitive reactance and inductive reactance constant values(i.e. independant of value of current in ac circuit at any time) ??

**Asked By: AAYUSH TANEJA**

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**Joshi sir comment**

Write the question with correct symbols

yes it is equivalent to resistance for that circuit

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

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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

**Asked By: SARIKA**

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**Joshi sir comment**

yes this method is correct.