Practice free NEET NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
Due to 10 Amp of current flowing in a circular coil of 10 cmradius, the mag. field produced at its centre is$ \ pi \times 10^{-3 } $ Tesla. The number of turns in the coil will be
$ B = N \left( { \mu_0 I \over 2 a } \right) \Rightarrow N = 50 $
The distance at which the magnetic field on axis as compared to the mag. field at the centre of the coil carrying current I and radius R is 1/8 , would be
$ { B_1 \over B_2 } = \left( { R^2 \over X^2 + R^2 } \right) ^{3/2} $ $ 2^{-1} = \left( { R^2 \over X^2 + R^2 } \right) ^{1/2 } $ $ { 1 \over 8 } = \left( { R^2 \over X^2 + R^2 } \right) ^{3/2} $ $ { 1 \over 4} = \left ( { R^2 \over X^2 + R^2 } \right) $ $ 2^{-3} = \left( { R^2 \over X^2 + R^2} \right) ^{3/2} $ $ x = \sqrt 3 R $
In a H-atom, an electron moves in a circular orbit of radius $ 5.2 \times 10^{-11} $ meter and produces a mag. field of 12.56 Tesla at its nucleus. The current produced by the motion of the electron will be ................. Amp
$ B = { \mu_0 I \over 2a } \Rightarrow 12.56 = { 4 \pi \times 10^{-7} I \over 2 \times 5.2 \times 10^{-11} }$
A conducting rod of 1 meter length and 1 kg mass is suspended by two vertical wires through its ends. An external magnetic field of 2 Tesla is applied normal to the rod. Now the current to be passed through the rod so as to make the tension in the wires zero is $ [take g = 10 ms^{-2}] $
$ f_{mag} = f_ { grav.}$ $ BI l = mg $ $ I = { mg \over Bl } ( \theta = 90 ^\circ ) $ = 5 Amp
A straight wire of mass 200 gm and length 1.5 meter carries a current of 2 Amp. It is suspended in mid-air bya uniform horizontal magnetic field B. $[take g = 10 m/s^{-2}]$. The B is
$ f_{mag} = f_ { grav.}$ $ BI l = mg $ = 2 /3 Tesla
Along solenoid has 200 turns per cm and carries a current of 2.5 Amp. The mag.Field at its centre is…………... Tesla
$ b = \mu_0 ni = 6.28 \times 10^{-2} = 2 \pi \times 10^{-2} Tesla $
Two concentric co-planar circular Loops of radii $r_1$ and $r_2$ carry currents of respectively $I_1$ and $I_2$ in opposite directions. The magnetic induction at the centre of the Loops is half that due to $I_1$ alone at the centre. If $r_2 = 2r_1$ the value of $I_2 \over I_1 $ is
For smaller loop $ B_1 = { \mu_0 I_1 \over 2 r_1 } ........(1) $ For bigger loop $ B_2 = { \mu_0 I_2 \over 2 r_2 } ........(2) $ $ but r_1 \lt r_2 \Rightarrow B_1 \gt B_2 $ $ { \mu_0 \over 2 } \left[ {I_1 \over r_1 } - { I_2 \over r_2 } \right] $ $B = { \mu_0 \over 2 } \left[ {I_1 \over r_1 } - { I_2 \over 2 r_2 } \right] ( r_2 = 2 r_1) $ $ B = { 1 \over 2 } B_1 $From the data $ {1 \over 2 } B_1 = { \mu_0 \over 2 r_2 } \left[{ I_1 - { I_2 \over 2 } } \right] $ $ \therefore { I_2 \over I_1 } = 1 $
For the mag. field to be maximum due to a small element of current carrying conductor at a point, the angle between the element and the line joining the element to the given point must be
$ 90^\circ $ $ dB = { \mu_0 \over 4 \pi } { I d l sin \theta \over r^2 } $ $where \theta = 90^\circ ; dB becomes maximum$
When a certain length of wire is turned into one circular Loop, the magnetic induction at the centre of coil due to some current flowing is B0. If the same wire is turned into three Loops to make a circular coil, the magnetic induction at the centre of this coil for the
$ B = n^2 Bo $ $ = (3)^2 Bo = 9Bo $
Along straight wire carrying current of30Amp is placed in an external uniformmag. field of induction $4 \times 10^{-4} tesla$. The mag. field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point 2 cm away from the wire is tesla.
$B_1 = 4 \times 10^{-4} tesla $ (parallel to wire ) $B_2 = { \mu_0 \over 2 \pi } { I \over y } $ $ = 3 \times 10^{-4} tesla = 5 \times 10^{-4} tesla $
Ready to ace NEET?
Free access · No credit card required
Yes. You can attempt every NEET question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.