# 13 - Moving charge magnetism and force in magnetic field 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

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

velocity of e^{-} in hydrogen atom is 2X10^{6} m/s . the radius of orbit is 5X10^{-11} m . the mag induction at centre of orbit in T will be??

**Asked By: SARIKA**1 Month ago

**Asked By: SARIKA SHARMA**

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**Joshi sir comment**

B = μ_{0}/2 * i/r

and i = e/T

and T = 2πr/v

solve

potential diff b/w dees of cyclotron is V , if charge q comes out of it after completing n revolution then gain in KE of charge is 2nqV HOW?

**Asked By: SARIKA**1 Month ago

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**Asked By: SARIKA SHARMA**

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**Joshi sir comment**

when charge will move from first dee to second dee it will gain qV and on returning to first dee it will gain qV again so in one revolution it will gain 2qV so in n revolutions it will gain 2qVn