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) becomes double
b) remains same
c) becomes half
d) None of the above
b) remains same
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
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
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 current loop placed in a magnetic field behaves like a
a) Magnetic substance
b) Magnetic pole
c) Magnetic dipole
d) all true
Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²
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
In the Young’s double slit experiment both the slits are similar. If the length of one of the slits is halved, which of the following is true?
(a) Bright fringes become narrower.
(b) Bright fringes become wider.
(c) Dark fringes become darker
(d) Dark fringes become brighter.
The electric potential of earth is taken as:
(a) zero
(b) infinity
(c) unity
(d) None of these
To observe diffraction, the size of the obstacle
(a) should beX/2, where X is the wavelength.
(b) should be of the order of wavelength.
(c) has no relation to wavelength.
(d) should be much larger than the wavelength.
The penetration of light into the region of geometrical shadow is known as
a. Interference of light
b. Diffraction of light
c. Refraction of light
d. Polarization of light
A square loop of side l , resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v , then the power needed is
(a) BRlv
(b) B²l²v²/R
(c) B l²v²/ R
(d) Blv/R
Huygens wave theory allows us to know
A) The wavelength of the wave
(B) The velocity of the wave
(C) The amplitude of the wave
(D) The propagation of wave-fronts