Question

If Be represents equatorial magnetic field and BA represents axial magnetic field due to a bar magnet. Which of the following relationships between BE and BA is correct?

• A. Be = 2Ba
• B. Ba = 2 Be
• C. Be = 4 Ba
• D. Ba = 4 Be

Answer 1

Answer: (B)

Ba = 2 Be

Answer 2

: As equatorial magnetic field due to bar magnet is

$\mathrm { B } _ { \mathrm { E } } = \frac { \mu _ { 0 } \mathrm {~m} } { 4 \pi \mathrm { r } ^ { 3 } }$ …(i)

and axial magnetic field due to bar magnet is

$\mathrm { B } _ { \mathrm { A } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { 2 \mathrm {~m} } { \mathrm { r } ^ { 3 } }$ …(ii)

From (i) and (ii), we get,