If a steel wire of length l and magnetic moment M is bent into a semicircular arc,
If a steel wire of length l and magnetic moment M is bent into a semicircular arc, then the new magnetic moment is
Options
(a) Mxl (b) M/l (c) 2M/π (d) M
Correct […]
Physics
If a magnet is suspended at an angle 30⁰ to the magnetic meridian, the dip needle
If a magnet is suspended at an angle 30⁰ to the magnetic meridian, the dip needle makes angle of 45⁰ with the horizontal. The real dip is
Options
(a) tan⁻¹(√3/2) (b) tan⁻¹(√3) (c) tan⁻¹(3/√2) […]
Two 220V – 100W bulbs are connected first in series and then in parallel.
Two 220V – 100W bulbs are connected first in series and then in parallel. Each time the combination is connected to 220 V AC supply line. The powers drawn by the combination in each case […]
Electromagnets are made of soft iron because soft iron has
Electromagnets are made of soft iron because soft iron has
Options
(a) Low magnetic susceptibility and low retentivity (b) High magnetic susceptibility and low retentivity (c) High magnetic permeability and high retentivity (d) […]
An electron in a circular orbit of radius 0.05 nm performs 10¹⁶ rev/s. The magnetic
An electron in a circular orbit of radius 0.05 nm performs 10¹⁶ rev/s. The magnetic moment due to this rotation of electron is (in A-m²)
Options
(a) 2.16×10⁻²³ (b) 3.21×10⁻²² (c) 3.21×10⁻²⁴ (d) […]
when a magnetic field is applied on a stationary electron, then it
when a magnetic field is applied on a stationary electron, then it
Options
(a) remains stationary (b) spins about its own axis (c) moves in the direction of the field (d) moves perpendicular […]
The horizontal component of earth’s magnetic field at a place is 3×10⁻⁴ T
The horizontal component of earth’s magnetic field at a place is 3×10⁻⁴ T and the dip is tan⁻¹ (4/3). A metal rod of length 0.25m is placed in N-S direction and is moved at a […]
In cyclotron, for a given magnet, radius of the semicircle traced by positive ion
In cyclotron, for a given magnet, radius of the semicircle traced by positive ion is directly proportional to (where, v=velocity of positive ion)
Options
(a) v⁻² (b) v⁻¹ (c) v (d) v²
Correct […]
If the dipole moment of a short bar magnet is 1.25 A-m², the magnetic field on its
If the dipole moment of a short bar magnet is 1.25 A-m², the magnetic field on its axis at a distance of 0.5 m from the centre of the magnet is
Options
(a) 1×10⁻⁴ […]
Magnetic induction produced at the centre of a circular loop carrying current is B.
Magnetic induction produced at the centre of a circular loop carrying current is B. The magnetic moment of the loop of radius R is (where, μ₀=permiability of free space)
Options
(a) BR²/2πμ₀ (b) […]