CBSE
A thin bar magnet of length 2 L is bent at the mid-point so that the angle between them is 60°. The new length of the magnet is
L/2√3
√3 L/2
L
2 L/3
A square loop is made by a uniform conductor wire as shown in figure
The net magnetic field at the centre of the loop if side length of the square is a
zero
None of these
Magnetic field at point O will be
interior
exterior
interior
exterior
Two long straight wires, each carrying an electric current of 5 A, are kept parallel to each other at a separation of 2.5 cm. Find the magnitude of the magnetic force experiment by 10 cm of a wire.
4.0 × 10-4 N
3.5 × 10-6 N
2.0 × 10-5 N
2.0 × 10-9 N
The parts of two concentric circular arcs joined by two radial lines and carries current i. The arcs subtend an angle 0 at the centre of the circle. The magnetic field at the centre O, is
A galvanometer acting as a voltmeter should have
low resistance in series with its coil
low resistance in parallel with its coil
high resistance in series with its coil
high resistance in parallel with its coil
A current I is flowing through the loop. The direction of the current and the shape of the loop are as shown in the figure. The magnetic field at the centre of the loop is μ0I/R times ( MA = R, MB = 2R, ∠DMA = 90o )
5/16, but out of the plane of the paper.
5/16, but into the plane of the paper.
7/16, but out of the plane of the paper.
7/16, but into the plane of the paper.
A circular current carrying coil has a radius R. The distance from the centre of the coil, on the axis, where B will be of its value at the centre of the coil is
2 R
If the electric flux entering and leaving an enclosed surface respectively are , the electric charge inside the surface will be
A current carrying loop is placed in a uniform magnetic field in four different orientations I, II, III and IV as shown in figure. Arrange them in decreasing order of potential energy
l > lll> ll > lV
l > ll > lll > lV
l > lV > ll > lll
lll > lV > l > ll