The ratio of magnetic length to geometric length of a magnet is
a) 0.084
b) 8.4
c) 80.4
d) 0.84
a) 0.084
b) 8.4
c) 80.4
d) 0.84
d) 0.84
Unit of magnetic dipole moment is
a) ampere meter
b) ampere/meter⁻¹
c) ampere metre²
d) ampere/metre²
A current loop placed in a magnetic field behaves like a
a) Magnetic substance
b) Magnetic pole
c) Magnetic dipole
d) all true
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
A current carrying small loop behaves like a small magnet. If A be its area and M its magnetic moment, the current in the loop will be
a) M/A
b) A/M
c) MA
d) A²M
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
The electric flux through a closed gaussian surface depends upon
(A) Permittivity of the medium.
(B) Net charge enclosed only.
(C) Net charge enclosed and permittivity of the medium.
(D) Net charge enclosed, shape and size of the Gaussian surface and permittivity of the medium.
For any charge configuration equipotential surface through a point is normal to the electric field.
1. Since W=Fscosθ is zero so field is normal to the surface
2. As W≠0
3. Work done can be Zero if Field is parallel to the field
4. None of these
The current sensitivity of a Galvanometer can be increased by decreasing-
a) Magnetic field B
b) No. of turns N
c) Torsional constant k
d) Area of the coil A
Which among the following isn’t a suitable phenomenon to establish that light is wave motion?
a) Interference.
b) Diffraction.
c) Reflection.
d) Polarization.
Three charges each equal to 2 μC are placed at the corners of an equilateral triangle. If force between any two charges is 2F, then the net force on either will be:
When interference of light takes place
(a) energy is created in the region of maximum intensity
(b) energy is destroyed in the region of maximum intensity
(c) conservation of energy holds good and energy is redistributed
(d) conservation of energy does not hold good
The electric potential of earth is taken as:
(a) zero
(b) infinity
(c) unity
(d) None of these