DATE____________
XII_ELECTROSTATICS, MAGNETISM &
EMI
Q1.
How can you charge a metal sphere positively without touching it? 2.
Q2.If
109 electrons move out of a body to another body
every second, how much time is required to get a total charge of 1 C on the
other body?
2.
Q3
2.
Q4. Derive the expression of the electric
field due to a charged sheet.
3.
Q5
2.
Q6 A 600pF capacitor
is charged by a 200V supply. It is then disconnected from the supply and is
connected to another uncharged 600 pF capacitor. How
much electrostatic energy is lost?
in the process?
3.
Q7 A circular
coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.10
T normal to the plane of the coil. If the current in the coil is 5.0 A, what is
the (a) total torque on the coil, (b) total force on the coil,
3.
Q8 (a)Derive the
expression of the capacity of a parallel plate capacitor and electric field
density?
5.
Q9.Two
charges 3 × 10–8 C and –2 × 10–8 C are located 15 cm apart. At what point on
the line joining the two charges is the electric potential zero? Take the
potential at infinity to be zero. 3.
Q10 Draw equipotential surfaces
for (a) a dipole and (b) two identical positive charges. 3.
Q11A slab of
material of dielectric constant K has the same area as the plates of a
parallel-plate capacitor but has a thickness (3/4)d,
where d is the separation of the plates. How is the capacitance changed
when the slab is inserted between the plates? 3.
Q12 If
one of the two electrons of a H2 molecule is removed, we get a hydrogen
molecular ion H+2. In the ground state of an H+ 2, the two protons are
separated by roughly 1.5 Ĺ, and the electron is roughly 1 Ĺ from each proton.
Determine the potential energy of the system.
Specify
your choice of the zero of potential energy. 4
Q 13.
Q 15. Answer carefully:
(a)
Two large conducting spheres carrying charges Q1 and Q2 are
brought close to each other. Is the magnitude of electrostatic force between
them exactly given by Q1 Q2/4π ε0r 2, where r is
the distance between their centres?
(b)
If Coulomb’s law involved 1/r3 dependence (instead of 1/r2),
would Gauss’s law be still true ?
(c)
A small test charge is released at rest at a point in an electrostatic field
configuration. Will it travel along the field line passing through that point?
(d)
What is the work done by the field of a nucleus in a complete circular orbit of
the electron? What if the orbit is elliptical?
(e)
We know that electric field is discontinuous across the surface of a charged
conductor. Is electric potential also discontinuous there?
(f ) What meaning would you give to the capacitance of a
single conductor?
(g)
Guess a possible reason why water has a much greater dielectric constant (= 80)
than say, mica (= 6).
Two charges –q and +q are located at
points (0, 0, –a) and (0, 0, a), respectively.
(a) What is the
electrostatic potential at the points (0, 0, z) and (x, y, 0) ?
(b) Obtain the
dependence of potential on the distance r of a point
from the origin when r/a >> 1.
(c) How much work
is done in moving a small test charge from the point (5,0,0)
to (–7,0,0) along the x-axis? Does the answer change if the path of
the test charge between the same points
is not along the x-axis?
24 (LGF) FEROZE GANDHI ROAD(OPP VLCC), LAJPAT NAGAR III N D --110024
EMAIL: INFO@SETONLINE.ORG
24 (LGF) FEROZE GANDHI ROAD(OPP VLCC), LAJPAT NAGAR III N D --110024
EMAIL: INFO@SETONLINE.ORG
9811870668, 9810395887
24 (LGF) FEROZE GANDHI ROAD(OPP VLCC), LAJPAT NAGAR III N D --110024
EMAIL: INFO@SETONLINE.ORG