The direction of magnetic dipole moment is always from
a) North pole to south pole
b)Away from North pole outside magnet
c) South pole to North Pole
d) all of the above
a) North pole to south pole
b)Away from North pole outside magnet
c) South pole to North Pole
d) all of the above
c) South pole to North Pole
Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²
Magnetic field lines form continuous closed loops
a) magnet is always a dipole
b) magnet is always a monopole
c) magnetic material is permeable
d) none of the above
A current loop placed in a magnetic field behaves like a
a) Magnetic substance
b) Magnetic pole
c) Magnetic dipole
d) all true
A bar magnet of dipole moment ’m’ cut into two equal pieces transverse to its length. Dipole moment of each part is
a) Remain same
b) m/2
c) 2m
d) none of the above
If a magnet is cut perpendicular its length into equal parts ,then the pole strength of each pole of the magnet
a) becomes double
b) remains same
c) becomes half
d) None of the above
A steel wire of length l has a magnetic moment M .It is then bent into a semicircular arc. The new magnetic moment is
a) M
b) 2M/π
c) M/l
d) Ml
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of
(a) \(10^6\) rad
(b) \(10^{-2}\) rad
(c) \(10^{-4}\) rad
(d) \(10^{-6}\) rad
When tiny circular obstacle is placed in the path of light from a distance source , a bright spot is seen at the centre of the obstacle.
I. It happens due to
II. Polarization of light waves
III. Diffraction of light waves
IV. Interference of light waves
V. Scattering of light waves
A young’s double slit experiment uses a monochromatic source. The shape of interference fringes formed on a screen is :
a. Parabola
b. straight line
c. circle
d. Hyperbola
In electric arc furnace Cu or Iron is melted due to variation of
(a) current
(b) magnetic field
(c) voltage
(d) electric field
Two capacitors of capacitance 6 µF and 4 µF are put in series across a 120 V battery. What is the potential difference across the 4 µF capacitor?
(a) 72 V
(b) 60 V
(c) 48 V
(d) zero
The amount of work required to increase the distance between -6µC and 4µC from 6 cm to 18 cm will be :
(a) 1.8 J
(b) 2.4 J
(c) 1.8 µJ
(d) 2.4 µJ
What type of wave front will emerge from any distant source of light?
i. Spherical wave front
ii. Cylindrical wave front
iii. Plane wave front
iv. None of these